Moving to Wembley, however temporarily, is not ideal for either Spurs nor Chelsea, but neither of them have any other realistic options at the moment. Spurs are scheduled to move there for 2017-18 (they’re already playing European games there this season) while Chelsea are likely to use it for the three seasons after that while Stamford Bridge gets rebuilt.
The one big winner in all this is the Football Association, who are the owners of Wembley and thus will get a handsome annual fee from the teams (once rumored to be as much as £15m per season). The annual fee may be a bit lower now that the potential groundshare is no longer a concern (delays in the approval of Chelsea’s plans have cleared that conflict up), so perhaps stemming from that, the FA are now trying to gain approval to host more full capacity matches at the stadium starting next season (presumably they get a cut of the gate and/or concessions and other such income).
According to the Daily Mail, the FA are set to formally ask Brent Council to approve an additional 20 games for full capacity. Current regulations allow for 37 games at the full 90,000 capacity — that number includes national team games and cup finals — and basically an unlimited number of matches at a maximum capacity of 50,000.
“Any application to temporarily increase the number of major events at Wembley Stadium for the 2017/18 season will be subject to a consultation with local residents and businesses. Following this, the planning committee will make a decision based on the merits of the application.”
-Brent Council spokersperson; source: Mail
While the spokesperson only talks about next season, presumably any precedent set with this decision will guide future requests to the similar. An additional 20 games would allow temporary tenants to play all home league games at full capacity.