It's not that the SaaS model can't be economical, it's that all these companies are suddenly expected to beat a much higher interest rate bar and must enshittify rapidly to squeeze their customer base. Since SaaS is absolute lock-in, they can... for a while.
The PC revolution and local software exploded when interest rates were high and in addition to the novelty and flexibility a major driver was cost reduction and having local control over cost. If you can run software locally on your own stuff you can decide whether to invest in an upgrade. If everything is a subscription to a remote system you have zero control, which seems like less of a problem when money is free. Lots of economically irrational things like variable-rate outsourcing with hard lock-in make sense when money is free.
Maybe those of us interested in decentralization and local-first just have to wait for the ZIRP era to unwind.
At that time (80s to 90s), computer networks weren't really a thing outside of institutional settings, so it wasn't like there was anything to compete with "local software".
What is different from the ZIRP inflating unsustainable startups. SaaS is a loan even when it's bootstrapped or financed in a normal way.
I'm not anti-SaaS by any means, but it's a cautionary tale about over-reliance on services that are way outside your control.