Unity cost 2.5% of your income, Unreal - 5%(if income is above $1M). There is no free Unity version. There is a version with runtime fee model and if you have less than 100k installations - it is free for you. But if you have more than that - they charge you 2c per installation. It counts repeatable installations of same game and newer versions as well. After community rant in last year - they promised to increase limit to 200k, but refuses to remove this runtime fee.
GD passed that limit long ago. I made some evaluation of download numbers, and only in this year - Unity would have charged him about $4k, about $1k per month, 20% of his income from Patreon. Unity is the most expensive game engine for indie developers. This is why you should avoid using it as much as possible.
Well, the plan Unity HAD, previously, and retracted was hilariously bad.
But both their current pricing for Unity 5 (which has no runtime fee model), and the current plan for when they launch Unity 6 (this year supposedly?) are complete different, and almost everything you wrote about it is wrong.
Since he's making about $32,510 a month ($14,740 from patreon, $17,770 from subscribestar... also god damn I'm in the wrong line of business), that's $390,120 a year.
If he were developing with Unity 5, he's over the $100,000 limit for Unity Personal, so he'd have to purchase a Unity Pro license, which costs $2,040 annually, or 0.5% of his yearly revenue. There is no runtime free.
If he were to upgrade to Unity 6 after it launches... Unity Personal's limit goes up to $200,000... so he'd still need a Unity Pro yearly license (and the price of that may go up, but I dunno), but the runtime fee thing only kicks in after $1,000,000 of annual revenue AND 1,000,000 lifetime total unique 'initial engagements' (which they define as the first time a unique customer legitimately downloads the product from a unique distributor (IE, if one person buy it on Steam and the Epic game store, that's two, if they pirate it, that's 0, and it also doesn't count repeat downloads from the same distributor, nor upgrades).
So Grim's total cost under Unity 6 would only be the Unity Pro fees, unless he suddenly gets up to over a million in annual revenue and a million customers... and if he does, somehow get that high, the runtime fee is capped at 2.5% of revenue (but could be as low as $0.15 per new unique initial engagement each month, which would require 5,400 entirely new customers downloading it monthly to hit the 2.5% revenue cap).
All that said, yeah, switching to Unity probably ain't the greatest idea unless there's some significant blockers in the html+ SugarCube code side.
