They were asserting their ability to unilaterally bring in new terms, and specifically with the per-install issue bring in terms that require data that was poorly defined and could potentially be arbitrarily decided.
It wasn't a money issue. It was a trust issue.
But I don't really buy the pricing argument. Most of that type of games are all made with Unity meaning that it wouldn't be too hard for all of them to raise prices by a few % with minimal impact. That mostly only applies to IAP not to ads but then again Unity was offering a discount/waiving the fee if you were using their platform (which is of course scummy and predatory but probably wouldn't have had a massive financial impact).
Overall yeah... they completely messed up with aligning their pricing model with their long term goals as a company. It was always highly suboptimal (the per seat license is almost insignificant for some companies while a significant barrier for smaller ones, contractors etc). They would probably still have been fine if they hadn't started almost literally burning money like complete madmen after the IPO for no reason. Instead they now have >$2 billion in debt (albeit low/zero interest) and nothing to show for it whatsoever (well besides IronSource to some extent I guess..) in addition to a still extremely bloated but also unproductive and heavily demoralized workforce.
However I still think that the $0.20 headlines did a lot of reputational damage (even if most medium-major customers did the math) and that could easily have been avoided.
The way they introduced the already the hardly fathomable changes was IMHO as amateurish and half backed as it gets. Literally a corporate suicide attempt, can't imagine what were they thinking...
Funnily enough nobody who paid attention was going to pay the $0.2 since it was only there to funnel developers to the pro tier which would have given them a significant discount on the per install fee (IIRC there weren't even any current customers who would have paid that much because the personal tier had a $100k limit which was removed and the fee only applied after it).
Unity just had such a horrible PR release and did an inconceivably bad job at explaining the changes that they mad an already horrible pricing model seem 5x worse than it actually war. It was so incoherent that nobody read past the $0.2 per install...