100% guaranteed contracts...so they need to wait a few years. And if you're a top draft pick, you're paid millions to wait and play. Not to mention guys getting paid $20M during their arbitration years. All of which is funded by us, the consumer. They're doing just fine.
Any changes that should be considered are for the mid/low minor leaguer scraping by on $25K/year and delaying his ultimate professional/working career while chasing a dream. It's those guys who will have long term issues, many of which they'll never over come.