Earlier quoted context omitted.
Your model of companies using Rails with 1000s of engineers is almost comically naive. Look at what Shopify and Github have to do to make Rails work for them. Also look at the non Ruby code engineers there are writing and ask yourself why they might be doing it. Rails is not a religion. It can be good at what it does without having to go on a crusade when people point out its substantial limitations.
you're seriously convinced they would have had no problems if they chose something else? every codebase that lasts that long and is used that much is going to face very hard challenges as it scales and meets new landmarks. the maintainable codebase from day 1 to day 5000 is (mostly) a myth. yeah maybe some other stack could have faced different tradeoffs. I'm also curious about YOUR choice of stack at this point.
In my day job I use mostly Rails. My team is starting to rewrite some of the services we own in Golang because Rails is no longer a good fit for the problems and scale we use it for. Rails was great to get started fast.
Nothing wrong with using a press instead of a hammer at some point, they are just tools.