Most teams didn't need crazy strengthening, just depth. Liverpool did that using youth, while City got Rodri and Cancelo. Tottenham, if they complete lo Celso, have also strengthened better (with Sessegnon and Ndombele), although you can argue they need a striker backup to Kane. Chelsea, with Pulisic, tried to compensate for Hazard leaving. Early days, but Pulisic will turn out to be a good player. Arsenal, I don't know, dark horses, but Pepe is a good signing for them, they need a proper CB though.
I get the optimism, but we have significantly strengthened because we needed to. Other teams didn't. A CM along a Striker would mean we would have had close to a perfect window. As it stands, City have had the best transfer window among the Top 6. Can make a case for Wolves outside it (Leicester too, if they were able to replace Maguire).
We still have an incomplete window (no matter how you look at it). We don't have the proper players to actually play a 3 man midfield (I'm not including youth players here - they will be backup). And an injury to Pogba leaves us screwed. So, while it has been a good window, and performances have been good in pre-season (pinch of salt), it can hit a barrier. But however, definitely can go into the season with cautious optimism, with the additions we have made.