The reality is most companies and products never blow bast the point of needed to ditch Rails. The argument made at the time was scaling horizontally is cheaper than hiring new devs, and you probably will never need to scale that much horizontally.

Test suite bloat is a different problem that stems from the lack of incremental typing which I think is what ultimately killed Ruby and Rails.

Any big Rails codebase can be a nightmare to grok unless people have been diligent about documenting what different methods return.