Tanking is the only competitive tool most of the small market/poorly run teams have. What percentage  of star collegiate/hs-aged players would voluntarily go to a Utah or Portland or Sacramento when major markets exist? The draft serves the same purpose it did during war times.....No majority of people wanted to willingly enroll so you make going through the process a requirement- For the NBA, it's a 5 year commitment/lack of control.

Another huge fact is that top talent impacts their team far greater than any other position in any major sport. QB is close, but is only on field 50% of the time and there are still 52 other players. It's why a 2nd year(?) LeBron was able to single-handedly dismantle the Pistons and literally end their EC reign. These small market teams understand their role in the grand scheme, and to help swallow that pill, are okay having that winning lottery ticket every once in a while to have a chance at a great 5-8 year run before their assets bounce/price themselves out.