Usually, if there is no alternative for something that's universally hated, the reason is the enormous resources needed for the replacement.
Want to make a better search engine than Google and Bing together? Sure, that's easy! Crawling, storing and querying the index - you don't have that money.
Want to create a better browser than Chrome/Firefox? Sure, go for it - just get 2 million work hours.
Want some OpenAI replacement? Get a few thousand GPUs first.
CloudFlare captchas don't let you through? Just build your own wordwide backbone along with a huge CDN network, and off you go.
etc.
No.
If only ...
Are you going to pay them to?
Yup also called the "phoenix effect" or "entrepreneurial recycling" or "second-wave innovation".
Not FOSS necessarily but you will see lot of new startups exploring new niches.
We saw it after the dotcom bubble burst, 2008 GFC, Cryto/NFT implosion 22-23 (shifting people to AI).
FOSS is mostly big tech funded these days. They use some library long enough, get dependent on it and then end up assigning funds for maintenance. Or the other way round where they build something internally - run out of budget to keep it running - open source to community.