Not here to comment on Segments engineering prowness, I have no clue one way or another. However; I think an overwhelming number of engineers and developers are mislead in believing that you have to have the perfectly crafted program/service/app/whatever in order for it to be successful.

It doesn't! Your tech stack has next to no impact on the success of your product.

Making something useful is really all that matters. Is the service running? Great, that's all the end user cares about. The back end could be a bunch of code copy-pasted off old form posts from 1998 and string together with scotch tape as long as it works.

The end user doesn't care about what language you use. They don't care if you use redis, mysql, postgres, or mssql 2000. They don't care if the HTML or CSS is messy. They won't judge you if you don't use SASS or LESS or whatever is popular today.

The most successful side project of mine runs on a $20/m VPS and has been re-written 3 times and the code has been pretty terrible every time because every re-write was done in a new language I learnt over a weekend and never touched again. The first was some horrible PHP, then some less horrible PHP, then GO, and recently someone re-write it (properly) in elixir. The end user doesn't know, the end user doesn't care. The site gets about 250K uniques a month and the API handles about 350 million requests a month. The crappy GO I wrote in a weekend worked just the same for the end user as the fancy elixir.

Anyways, sorry for the rant. I've just seen so much wasted effort go on projects that never launch because people are too concerned about stuff that really doesn't matter in the long run.

If your stuff runs like crap because it found a market fit and you have people signing up and your crappy code can't handle it, then that is a FANTASTIC problem you now get to solve.