There are a LOT of places that accept freelance writing, yes. Thousands! A writer can go nuts trying to write pieces that are right for one particular publication. The editor may or may not get back to you. They may or may not appreciate your pitch. Your story may or may not fit in with what they want. All that takes hours and hours of unpaid work.

With Medium, I spend my day mostly writing, not mostly pitching and researching. I could run myself ragged trying to pitch to a dozen different sites. There are thousands of sites out there you can pitch to out there. If you're writing for a general audience, most will not pay what Medium pays.