I'm going to let you in on an open secret of the industry: a lot of SaaS companies were already zombies, only running around because of the large amount of debt they managed to obtain during the ZIRP era.

I am self-employed but I'm tempted to replicated buffer in-house for my social media management. I feel that they are adding a bunch of pointless features while the core of the product is less and less stable.

Data sovereignty is the critical factor. If bringing the data back in-house increases security, robustness then there might be a business case for replicating only that portion of the SaaS app that is actually being used.

Replicating software with AI is not zero cost issue. Not only do you need to pay for tokens used, but still have in-house tech and support costs to consider. Unlikely to be a strong business case for replication on those cost/ROI basis alone.