The football case is the simplest one.
Off the pitch, the gap may be just as important.
That is not just branding. Bigger gates usually mean stronger recurring matchday income, and stronger revenue gives clubs more room to absorb mistakes.
Chelsea still carry elite-club weight, but recent seasons have looked fractured. Reports suggest they finished outside the European places, then slipped again in the league, while managerial change returned to the story. Heavy spending has continued, yet the league form has not consistently matched it.
That is the key contrast. Arsenal look settled. Chelsea still appear to be searching for a lasting structure.
This debate is not one-sided. Chelsea’s modern-era trophy haul remains formidable. Reports say they have won 24 trophies in the Premier League era, compared with 16 for Arsenal, and their European record includes two Champions League titles.
So the historical argument is still alive. The current one, though, feels different.
The next step is obvious: Arsenal must turn momentum into staying power, while Chelsea need a season that looks coherent from August to May. That is where this London argument will really be settled.