I think Mike’s success is awesome. Sidekiq has created so much value for startups in our industry and can operate up to a scale very few companies have to actually worry about. Other folk have reproduced similar in other ecosystems to success as well (see Hangfire) and there’s another half a dozen ecosystems out there where a motivated person could capture the same value.

The only downside I see is that it’s definitely led to the proliferation of commercializing OSS libs by making them slightly worse on purpose and adding a “go pro!” version. All too common these days. But again, can’t blame anybody on this path - creating good software isn’t easy and people do deserve to be paid for it.

The other place ripe for opportunity is Django-admin style tools. It’s been out for a decade maintained and free and it’s just an awesome tool. There are similar frameworks in Ruby, PHP (part of laravel’s pay to play offering), and Elixir, but not too much outside that. I’m pretty darn surprised there’s no Java or JavaScript world admin framework that can be plugged into with code. (react admin and the like are too low level, and being SPA centric don’t fight the whole battle - getting 95% of the way with no code other than pointing at a model is the real value add). One could also make oodles of cash in .NET here i imagine