Not sure what you mean. Surely more than 3% of the freelance talent pool is being used by companies at any one time.
In fact, I'd say my issues with sites like these is that most of them are exclusively for people who aren't that good.
I don't know about top 3%, but I'd say I'm in the top 25% for what I do and I have a hard as hell time finding top 25% clients.
I did the most remote freelancing at the earliest point in my career, while still learning, and given the cost sensitivity of most companies that hire freelancers, I'd say it works real well for that.
Just send the emails. You'd be surprised how crappy your competition is.
As noted elsewhere, that top 3% is just the gimmick of TopTal. They filter based on Codility tests. You can prepare for the tests there as well: https://codility.com/programmers/
I am not kidding. By design that site eliminates 97% of applicants -- be it front-end or mobile development or Python or Java or Go language.
Can people who are learning still do remote freelancing?