Well, it's possible for sure - but not necessarily. And even if that's the case, it's a question of how much skill one is expecting from a small H-Game developer. I mean - just look at titles like 'Ark' - a game with no clue how many players/owners but a developer behind it who still isn't able to produce optimized maps on the chosen engine. Not that I defend anyone from producing sub-par software - but reality shows us that you only can't expect so much. It's unfortunate - but not particularly much you can do against it.
But there is another point in this quote I think is way more important to figure out what is really the source/reason for the bad performance. It's the "There's other game like these which have no problem" and my response to it would be; "Are there any?"
On the surface L&S:SB looks like any other RenPy dating sim - sure - but this game does some things that are only really found in some other titles I know of. Especially the conditional way it renders the NPC models. While most games in this genre use simple 2D graphics from a pool, L&S:SB uses a dynamic way to generate the NPC bodies out of single elements depending on conditions. So if the performance issues come from the rendering process, this might be the main candidate to look into - simply because the game has to load (and previously check variables) way more individual graphics like most other game.
The other aspect are the variables themselves - there are quite some in the game in its current state - and I would expect it being way more than most dating sims use - even those who work with RNG generated routines and are more based on a sandbox experience. That's the point I lack most knowledge in regards to RenPy though - I simply don't know how good the framework actually is doing that stuff. And since it was initially made for something different in mind - something that never would need so many checks - it's likely that the engine itself is just particularily poor in handling things.
Both aspects don't exist in their own bubble though - so it might even be that both are relevant and are reducing the overall performance. And on top of that it might as well be that badly written routines pile on top of this limits as well. The problem I see in such cases is if a small dev is actually capable of fixing/improving on such issues - you have to be a GOOD coder to develop a code backbone/framework that's optimized as well - in many instances that's actually one of the more often used aspects to decide between a mere 'coder' and a good one. At least I know that my company uses similar aspects to decide who to hire - since it often shows who merely has a basic education writing code and who really UNDERSTANDS what they are doing.
But at this point we intersect with your other point...
THIS I can fully support. If you offer your software on official channels to the market, you sure can be judged by universal standards - and you SHOULD imho - because that's the only way responsible consumers are able to shape the market into a direction of improvement.
Someone sells a €60,- VN with poorly made renders, 6th grader grammar & a buggy save-mechanic? Doesn't matter if you're only two guys on college - don't put it up for ten times what it's maybe worth then! Simple as that.
So IN GENERAL I'm all for harsh but rational criticism to weed out the market - there are already way too many people throwing cash at projects and developer long before they present anything really and are artificially keeping a market alive that should better just die out. Such people are part of the problem and are making things worse for EVERYONE - because THEY THEMSELVES are not getting GOOD game that way, but by giving fertile soil to shady developer they are also helping that the market can produce shit and gets away with it. And why should a developer do/invest more than necessary as long as they are making cash?
BUT...
I actually went on Steam right now to check L&S:SB's entry to check on the details myself. And well... it's €17,- full-price... that might be high enough to judge it by some standards - but still too little to judge it by regular AAA or even Indie standards imho. Yeah, it IS an official product and therefore should aim for technical stability even before content - but well... I've remember buying 50,- full-price games on physical discs in the late 2000s I never actually were able to play, because they didn't even install correctly from disk. And I don't mean they didn't installed correctly ON MY SYSTEM - no, they had inherent issues making it impossible to use those discs even on modern systems - at a time constant internet-access wasn't as prevalent as it is now - games from somewhat popular development studios...
So... well... I really can't go TOO hard on this game considering all those aspects. It's a relatively cheap game - it's officially labeled 'Early Access' what seems fair to me - it works at least okay-ish on many systems - the development-cycle is a bit slow but rather consistent (at least compared to other projects in the genre) - and it builds on a quite innovative and actually more than solid game-design-idea even if the execution lacks polish and it's wasting some of that potential...
In times when about 95% of overall developed game projects are apparently made by people with zero talent for gamedesign but some basic knowledge in coding on Unity having such a rough gem is actually worth something. Maybe that's just how much gamers have lost their edge and standards over the years - guess that's quite a possibility - but it is what it is.
Even if the execution won't produce something 'solid' in the end... I, as a 'hobby game-designer' myself can at least see that who ever came up with the game design has some talent for it - you get some keen intuition over the years for who knows shit and who is just copying something that already was made by someone with more talent before them...
That I unfortunately can't answer myself - it shouldn't be that hard to compile the hotfixed master for Android as well afaik - since RimPy apparently has quite solid functions to compile for multi-platform without much additional work necessary. It might be that it's just we on F95 not getting the files - but I have no clue who's responsible for providing/uploading them or how the process works in practice.
From what I can see, v.21.7.2b IS in fact listed for Android over on Itch.io - so it appears as if the patches are in fact available for mobile. So it might just need someone to provide the files over here as well.