I'm relatively new to the game, so I'm hoping this post is taken as a "food for thought" contribution for you more knowledgeable folks to discuss rather than any sort of expert opinion.
As far as I can tell, having a bad team results in two things: first, high draft picks which pretty much directly leads to great players; and second, low player salary, which can lead to better IFAs. The only drawback (I can see) to tanking is an owner has to endure some "bad" seasons. But, if your goal is to cut salary and get a high draft pick, a tanking owner has just as much to root for during their season as a winning owner -- the race for the top seed in the playoffs is nearly identical to the race for the top draft pick. The inherent downside to tanking seems ambiguous to me.
So my question is: what kind of effect would modifying the salary cap have? In an overly-simplistic view, real-life success generally leads to an increase in fan interest and therefore an increase in money. Lack of success leads to a manager being fired (seems like minimum wins can approximate this) and also for an uninterested fan base. If competing for a WS is not enough of a reward to keep owners competitive every season, is there some sort of incentive that can be tied to success, such as a higher cap or a better chance for Free Agents to sign, that could be instituted? Basically, it seems there isn't a clear counter-balance to the advantages tanking gives -- if some sort of benefit was given for a team with prolonged success (or even just a lack of losing), maybe that would give more of an incentive to stay competitive?
Anyway, just my 2 cents, and apologies if this has been covered before -- in which case, think of it as a chance to educate a newer player, and I would appreciate it!