They've played a lot of good baseball over the past 3 and a half years. This year isn't just a 1 year wonder, flukey outlier type of season.
They won 90 games in 2021, 90 games in 2022, and 88 games last year. Sure, only 1 playoff appearance is disappointing, but the results over the past 3 seasons (and now this season so far) is encouraging considering the previous nearly 2 decades. At the very least, they've been taking steps in the right direction for 3 and a half years now.
And while my intent isn't to "excuse" the lack of playoff appearances, I do think it's fair to acknowledge that the AL has been a stronger league than the NL. In 2021, 90 wins gets you into the playoffs by a comfortable margin in the NL, but misses the playoffs entirely in the AL. The Phillies had 87 wins and not only made the playoffs, but made it all the way to the WS. Last season, the Diamondbacks not only made the playoffs in the NL with 84 wins, but made it all the way to the WS. To put it another way, the M's had more wins than than the NL teams that made it to the WS in both 2021 and 2023.