Wesley,
As the father of a customer of Kyle's who totally buys into what Kyle is teaching, I believe you can learn (and work) to throw harder. I also believe uninformed effort can be counter-productive, no matter how diligent or intense.
My son didn't get much coaching early because I thought I was raising a wrestler, not a baseball player. If I had to do it over again, I'd have invested in better coaching sooner.
Best wishes,