> Wish Flask had a better ecosystem of extension around it So many extensions are unmaintained like flast-restful/openapi...

There's not much we can do about it I think. It's the blessing and curse of Flask.

For example you can combine Flask + Flask-Classful + Flask-Marshmallow + Flask-JWT-Extended to build an API in a really really nice way IMO, but OpenAPI specs are lacking because these are 4 distinct tools that are being glued together.

If generating OpenAPI specs is a top priority someone would need to bundle together the major components of an API (routing + serialization / validation + authorization) into 1 library in such a way that it's better than combining a few smaller libraries together. But if you're looking to build such a large library then it kind of goes against Flask's philosophy of being a micro-framework where you bring your own batteries.

If you want full blown batteries included for an API based app then you're probably better off using Rails (even for building APIs) or Django with DRF.

I'll admit it's not a great outcome tho. I really do think Flask-Classful + Flask-Marshmallow + Flask-JWT-Extended is a great combo but as someone who has been using Flask for 7+ years, have courses on Flask and have built a ton of apps with it when a client wants to build an API driven app where OpenAPI specs are important then I've gone with other solutions. Thankfully most of the apps I build return HTML and Flask is still great for building non-API based apps.