Startups can be acquired for a lot of reasons that have little to do with the exact MRR/ARR — team, technology, acceleration of time-to-market.
If an acquisition is to acquire something with scale, to build upon, most Big Cos (and not coincidentally, most Private Equity firms) aren’t too interesting until you are past $8m-$10m in ARR, and ideally, reasonably capital efficient.
Those are the SaaS businesses BigCos and PE firms can add layers of management, marketing pushes, etc. beyond. The ones already with proven brands and go-to-market strategies.
Most BigCos won’t see anything much below $8m-$10m in ARR as “proven” or having yet broken out in the market.