A "Pro" user to most companies is someone who can send / receive emails, and create / edit / share documents, plus google things they don't know.

A "regular" user is one who uses their device primarily for consumption; facebook, netflix and music.

The missing tier is "creators", developers / designers etc - and they find themselves lumped in with "pro" users yet their requirements are just a little bit higher. The market for "creators" is marginal, so it'll never be a focus.

For full control, there's "enterprise" versions of most software but come at a huge cost. This is where some "creators" find themselves as well when "pro" doesn't quite cut it, but generally find "enterprise" is overkill.