They might get more revenues, but it's going to drive up costs, not only in travel expenses, but in wearing out the players from excess travel in mid-season.

London would be heavily disadvantaged for free agents. Its salaries would be taxed in the UK, not the US, which would cost more. There would be currency risk, just like Canada faces in the NHL. Your players would either face multiple trips across the 6-9 time zones to play games, or face long road trips to the US before finally get a home stand.

As a player, I'd saying being in London would be a huge disadvantage. Better to visit during Wimbledon in the off-season than try to make a living there in a US-dominated league.