If I were a single indie dev with a game that was 90% complete in Unity, I think it would be fair to myself to say "well, this will be the LAST game I build in Unity".
It would be important to see if the changes would bankrupt you and also consider the possibility that the pricing gets even worse on a moment's notice as they have already proven they will screw you over. Finishing the game could be worse than starting from scratch if they pull this shit again.
A lot of developers have really tight profit margins and/or their current projects heavily rely on what Unity provides. "Cutting their losses and move on" would mean bankruptcy. They might be able to switch to other engines in the future but right now leaving Unity behind is not a valid decision for them.
And I work as a software developer. You can't just suddenly leave the software behind your business is based on. For a lot of VR or WebGL related Companies there is no alternative to Unity.
Also they are not broke right now and most likely won't be next year because of Unitys policy changes. Most devs won't be affected at all. Why just give up your hole business now because there might be problems in the future? Staying with Unity now gives us time to change the business model or find another technology.