a few issues here - c++ is not used that widely in embedded (most prefer c or a small c++ subset). and ruby? i can't remember the last time i saw a post about ruby here. and finance is huge.
Ruby still has relevance as it was the lingua franca of the 2010s ish startup scene. These days those startups have become veritable big tech companies in their own right - Stripe, Uber, AirBnB, and so forth. While many of those companies have started integrating other languages they still have massive legacy ruby codebases and demand then for ruby engineers.
all those companies you mention seem to me to have a 50/50 chance of going down the tubes. not because of their use of ruby, of course. still, i don't see any company started today to base their software on ruby. probably just me being wrong.
as a rails dev, if I were to start a new project today I would still pick rails. It makes building web apps a breeze. The technology is mature, stable, active and still staying modern in terms of integration with modern JS
you start running into problems as you scale, but the reality is you will run into scaling problems regardless of what technology you use, and the ability to move quickly and iterate is much more important for new projects than solving scaling problems before they exist
haha but then I have to learn the entire .NET / windows ecosystem which is a huge jump considering i've only ever developed on mac/linux. I am using wsl now though
and running circles won't matter because for most web apps the DB is usually the bottleneck anyway
But you can use .NET on both Linux and Mac. As for DB being the limit, usually that's only the case for simple CRUD apps. In microservices and high load apps, performance matters.
microservices start being useful when your monolith becomes too large for your engineering department to work on simultaneously. If you force good engineering practices and quality code reviews, you can scale this up to at least 100 devs. Microservices are more about Conway's law
high load apps I agree with, pick the technology that is appropriate, but again, for new projects I would say any technology that gives you speed of development (like rails) is far far far superior to speed of the technology.
