The thing is that there’s a need to integrate all these little tools because the problems they solve is part of the same domain. And that’s where problems lie. Something like Excel have an advantage as being a common platform for both data and procedures. Unix adopted text and pipes for integration.
LLMs are excellent at helping non-programmers write narrow use case, bespoke programs. LLMs don't need to be able to one-shot excel.exe or Plantio.apk so that Christine can easily track when she watered and fed her plants nutrients.
The change that LLMs will bring to computing is much deeper than Garden Software trying to slot in some LLM workers to work on their sprawling feature-pack Plantio SaaS.
I can tell you first hand I have already done this numerous times as a non-programmer working a non-tech job.