Our quality young players like Saka, ESR, Martinelli, Guendouzi, Saliba and KT were already at the club when Arteta took over. Emery had already brought Saka into the senior side by the time he was sacked.
That is true but needs a bit of qualification. Saliba was on loan, Saka had started three league matches as a wingback, Martinelli was an 18 year old who had just got his first league start, and ESR was barely on the fringe of the first team. Those guys were in the Arsenal organization but were hardly major parts of the squad, not much different than say Patino and Balogun right now.
Guendouzi and Tierney were really the only young established first team players. This is only my opinion but I think Guendouzi was never going to work out with a manager like Arteta because he is a tactically undisciplined player who wants the freedom to wander around the pitch and that is never going to work in any kind of disciplined tactical system.
Largely the roster was a dumpster fire. Mustafi, Kola, Luiz, Sokratis, Chambers, and Bellerin were our defenders who played the most minutes that year. Guendouzi, Xhaka, Torreira, Ceballos were our central midfielders. Honestly, Xhaka is the best player of those 10 which really says a lot because he is somebody we still need to improve on. Attack had more talent but also huge headaches. We had just spent 200m on three forwards who couldn't play together but also couldn't be moved on due to age/wages/Covid, only one of whom (Auba) was even good enough and he was 30.
Arteta has had a stronger squad and achieved worse results than Emery did, to date. It looks like that's slowly turning around though.
Arteta has gotten 1.72 points per match in the PL while Emery has gotten 1.73, so I wouldn't say his results have been worse, especially given that he won a domestic cup too. More importantly, Arteta has a plan for building a team around a modern philosophy whereas Emery never demonstrated any semblance of a plan for how to build a team.
Arteta is arguably lucky to still have his job after the disaster of fall 2020 but the club stuck with him and we appear to be reaping the benefits of that decision.
Arteta and Edu can have some credit for easing the wage pressure we were under, and they deserve credit for signing quality players like - Gabriel, Ramsdale, White and Ødegaard.
But conversely Arteta pursued and signed Willian, Mari and Soares. All three were absolutely not good enough, and who didn't see that coming at the time? We were the only club to offer Willian three years on big money. Only club to offer Soares a four year deal on good money. Only club to sign a 26 year old CB who had toiled away in Holland, Segunda Division and Brazil.
It's certainly been a mixed bag.
I agree that recruitment has been a mixed bag but most of Arteta/Edu's mistakes in the market have been when they tried to go cheap (Willian, Mari, Cedric). When they have spent significant money on fees, their record has actually been pretty good. White, Partey, Odegaard, Ramsdale, Gabriel, Tomiyasu all look like successful transfers. Going six for six on your biggest purchases doesn't happen that often. The jury is still out on Lokonga but at worst we'll probably get our money back or close given that he is young and on cheap wages.