The Arsenal thing is very weird and a perfect example of distorted narratives. The Wenger years were 5 PL titles plus 20 years of CL participation, plus domestic (mostly FA Cup wins).
The praise is very odd, they went from 8 strait years of being in top 2, from winning the title 5 times and constant CL participation to a club that hasn't won the PL in 20 years (yes, 20), hasn't won the league cup in 30, have been out of CL for 5+ years and basically have kept up appearances by focusing/winning FA Cups. While obviously that's more success than us, in the last 20 years it's been a fall from grace, not a success story
Kind of - depends on how far back you look. I'd say that they've been firmly de-established as a CL team having not been in it for 5 years, and therefore getting a 2nd place finish and qualifying is clear success.