Arsenal fans seem to forget that bar Spurs you were the only team to go into last season with stability, Chelsea, United and City all had new managers, you should have taken full advantage of that and pushed for the title as Spurs kind of did, instead you finished 5th. You have to assume all those 3 clubs will improve considerably purely through the manager having had a year to settle, and get his style drilled into his team. That already puts you at a much greater disadvantage than last season before you even begin to factor in signings and in your case potential loses.
Arsenal want to be title rivals, but the harsh reality is they haven't been for a long long time now, and it's virtually impossible for your team to make that leap this season now that you don't even have champions league and can't attract the quality needed to do so. Lacazette is a decent signing but the Arsenal mania crowd that seem to think it suddenly elevates you to title challengers are seriously deluded, your Keepers fine, your defence is a shambles with Koscielny the only competent CB you have at the club with zero cover at fullback and your midfield is almost non-existent. Who in the Arsenal midfield would even make the squad of Chelsea, City, Spurs or even United? Your attack is fairly strong and the only position where it's comparable to teams above.