This is just not true. It was relatively easy to obtain a copy of visual studio if you tried for relatively cheap. I know because I used their tools all through high school, college, and beyond and was actually rather poor during those times. They never tried to leech your revenue from you either in a scummy fashion later on once successful either.

Microsoft was very active in giving free licenses out for education, but those licenses often wouldn't allow for commercial use. If you've never been through a license audit, their legal team would usually make you pay through the nose or suffer through a lawsuit if they found you weren't using the right license for your dev tools.

That said, they'd generally target bigger businesses over smaller dev-only shops.