I think the exact opposite is true, B2B SaaS apps don't need to be an SPA to deal with fancy variants of a table. You can create highly interactive UI with things like Rails and Hotwire, sprinkles of JS or even HTMX. SPA's are bloat and often driven by designers who focus on flashiness rather than good UX.

Even if you use Rails or HTMX to get it done, you're still building an SPA.