This is a different NBA than you old people are used to. LeBron went to Cleveland. Howard spurned LA for Houston. Bosh stayed in Miami over Houston. Duncan never left SA. Big markets definitely have a big pull...but it wasn't the end all be all it once was. Oh, and all the big market teams suck.
If you are Durant, do you leave a team that can win it all to go to LA for less money than you'd get staying in OKC? I don't know, but it isn't the slam dunk leave small markets for big markets anymore.
Free Agents in 2016:
A: Kevin Durant, LeBron
B: Al Horford, Joakim Noah, Dirk Nowitzki, Dwight Howard, Kobe Bryant, Damian Lillard
There are two players that are franchise changers: Durant and LeBron. Those two make you a contender no matter how bad you are. LeBron probably isn't leaving Cleveland. Durant might leave OKC, but he'd be leaving a lot of money on the table to leave OKC.
So, if you are LA, your hope is to get Durrant and pair him with Kobe and Noah.
That's about it as far as big market hopes go. Maybe go watch Anthony shoot it 30 times a night in NYC?
What happens if Durant stays in OKC, because he doesn't want to leave Westbrook to go play with Kobe?
Then large market teams are SCREWED. BUT, they will have to do SOMETHING to appease their fans. So, then they start handing out max deals to players like Noah, Horford, and older players. That isn't going to help an LA out. That will screw an LA over, because now they will be good enough for the playoffs, but not good enough to attract a big free agent in 2017 and not bad enough for the draft.
Anyhow, I don't think this will be that big of a deal for two reasons:
There aren't that many "superstar" level players on the market
and
players can earn a lot more money staying with their team than leaving. And the endorsement deals aren't that different city to city anymore. You can still get a 200 million dollar shoe deal staying in OKC.
What would you do? Make 350 million competing for titles in OKC, or make 375 million losing in LA?
What will give large market teams a big advantage is the luxury tax. They can pay to make a mistake with an Horford or Noah. Small market teams can't.