Wasnt just talking about last update. I have been following his work since the previous game. For example 0.1 -> 0.2 we would get 7-10% each week like clockwork. Once in a Lifetime was even faster than that iirc. He was extremely fast not just for the few months he took to make the last update but for several years before that from the time he was making his previous game.
The time delay this update makes a lot of sense since each updates gets more complex the more the developer improves. And because more work is involved, trying to do all that additional work while maintaining the same rate as before would lead to burnout because you are trying to do a lot more work in that time. And I think that may be what happened last update. Personally I am fine with the current rate and I like that we are getting really high quality content. And maybe others are not and are fine with the lower quality of stuff like once in a lifetime. But I dont think anybody can accuse him of milking there is definitely work being done and the results will probably be obvious in a month or two when the next update drops.
IIRC Cari mentioned that the pandemic helped a lot with OIAL's dev prog since he would just be cooped up in front of his potato and there's little else to do besides working on what he originally considered a "side project to pass the time," so there's that.
Also again, there was no danger of burnout last update since he already reconfigured his schedule to deliberately go slower instead of his past dev speed where he was working harder and producing bigger content. With 0.5 you had 4 full scenes (compared to the usual 3), 1 semi-freeroam, a somewhat longer narrative compared to 0.4, loads of side characters with hand-crafted designs (hell Cari mentioned he had to go back and redo some of the renders in that event because he had to add more people because initial reactions was that it was too sparse for a college party), lots of backgrounds/assets to juggle with...
...and all of that while working like a madman possessed on his lonesome, with only a writing editor to help him out. Yeah, no shit he wanted to reconfigure his sched so he could take it a bit easy after that, maybe even hire additional help in the process.
TL;DR, he isn't going deliberately slow mainly to focus on quality over quantity, he's doing it also to maintain his sanity/prevent burnout*. It's a self-imposed limiter because he knows that he would just try to push himself to work harder than before in order to meet a personal deadline that no sane indie dev would ever try to meet unless they were an absolute workaholic. And Cari has proven in the past that he is indeed a damn workaholic.
(I mean his old prog speed and comments he made in the past like the ones posted above just point that he is, really)
Plus some of his recent comments also support the fact that he knows he can be faster. He's just trying not to and pace himself properly. For good reason.
*Edit: Found the quote where he first mentions the change of sched for said reason (and also everything I said about him pushing himself a bit too far with 0.5)