Well, there is no use fighting the velocity issue. It is the key that gets a pitcher noticed and developed. If a guy dosen't have velocity they need to work on core strength and their mechanics. Strong legs, muscular buttocks and deep core strength coupled with continued work on developing effective mechanics will produce results. A kid just has to be patient. Nothing happens over night, but with persistent work over several years will produce results.
I have seen two schools of thought on whether velocity is a God given talent or can be developed. You either have it or you don't. Therefore, don't fight mother nature. I tend to believe it is a combination of both to some degree, but regardless, if a pitcher does not work harder than anyone else on his team at his craft others will and ultimately natural talent will be overtaken by good old fashioned hard work.
A friend of mine is a good example of the hard work argument. When he graduated from HS he was an average pitcher throwing 80 to 82. He was a walk on at a JUCO and after two years increased his velocity to 85 and would on occasion hit 88. After 2 years he was recruited by a large D1. As a junior he would occasionally hit 90. In the summer between his junior and senior year he began a core strength workout program. He then regularly hit 90 to 92. He was then heavily recruited by the pros and signed after his senior year. The first year in the pros the club re-worked his mechanics. After this one year he began to hit 95. Point is he was 24 before he hit 95. He grew, matured and developed his mechanics to maximize his potential. Although he did not make the show he played for 10 years on mostly AA and AAA teams.
For some, velocity can come more naturally, but for others it can be attained if they are willing to put in the work. That's the key that will seperate those who can from those who could.
I believe it is up to the kid. If they are willing and able...with proper guidance and direction to avoid un-necessary injuries, then yes, velocity can be achieved through determination, tenacity, sacrifice and work.