I think the context here is super important: I run an agency, and a lot of our clients are small startups or solopreneurs. The most important factors in determining their tech stack are (in some order):

* Time from idea to deployed solution * Ease of pivot * Ease of finding other devs who can take over

If I were a staff engineer at a large company with an existing tech stack tasked with spinning up some new internal microservice, I'm probably not choosing Rails.

But if I'm truly greenfield on a strict budget, still searching for product market fit? If that application ever truly outgrows rails (and it can become wildly successful without doing so --- look at stripe, instacart, github, shopify) then we've already won by surviving long enough for rails to be the problem.