By September Arteta will have spent over £850m as Arsenal coach. Yet he hasn't won the league or CL and we're likely starting with Madueke and Havertz** as forwards when the new season begins. He's had more freedom to buy who he wants than Wenger.
90 points in the league is the minimum he has to achieve or at least get to a CL final.
His job is a hot seat now. He's made a fair number of enemies among Arsenal fans with the Partey scandal so I don't think the fans will be as easy on him as they were last season through the shit football and being out of PL contention halfway through the season.
** IMO Arteta will not start the season with Gyokeres in the first XI.