There are benefits to specialization, and will be for a long time even with AI. It's worth a premium to not limit all my software to what I and my agents know, and to be able to rely on other people to fix it if there's a problem.

Investment size for software plays is going to drop, and people will still invest for the same reason they do now: solving problems for people is valuable. Marginal costs dropping will bring down a lot of costs in various places, but the software itself is only part of what SaaS provides.