Ozil and Sanchez weren't mega names. Ozil was the bigger name. But, they've won nothing in recent years either. City on the other hand have had massive media exposure in recent years, and winning the PL twice has really put us on the map and made our brand exciting. Arsenal make more from merchandising and matchday revenue than we do, we make our money from other streams (some of which are arguably questionable, depending on who you choose to believe!) - namely broadcasting and commercial. I would also argue that our choice of signing in recent years like Aguero, Tevez, Toure, Silva etc have a stronger appeal than Arsenal's - but it's debatable, for sure.
Of course it's complex, and we're doing fantastically well, but I think we have to accept that levels of investment necessary have been exceptional, and far greater than most other 'investors' could manage.
They say you need to speculate to accumulate, and because we've been able to speculate far more than others, that's why we've accumulated. Others simply haven't been able to speculate to the same degree (or have been unwilling to do so, because of the risks involved).