I can't imagine it would ever be worth, under any scenario, trying to write/build/support any $25/seat SaaS software for any company I've worked at in 25+ years.
Another thing to keep in mind - very little of the cost of a SaaS license is the time it takes to build the software. Security, Support, Maintenance, Administration, backups/restores, testing/auditing said backups/restores, etc, etc.. and then x-training new SREs on how to support/manage this software, ...
Even as someone who spend 10+ hours a day churning out endless LLM applications, products, architectures from my myriad of Cursor/Codex/CC interfaces and agents - I'm dubious that LLMs will ever eat into SaaS revenue.
I'm sure (lots of) people will try - and then 1-2 years in someone will look at the pain, and just pull the ripcord.