Oh yes, dropping to 5th or 6th would be really bad. I'm just making the point that it shouldn't take that for his seat to be hot.
In the last 6 years there's only a place or two in the league that have separated them from a team like Tottenham in the 'also ran' category.
The consistency is nice, and it's not a trivial thing to do to finish 3rd or 4th and make it out of the CL group stage repeatedly, but if you're Arsenal you should be demanding at least an occasional honest look at a title. It's been what, a decade? since they've been within 10 points of the title. That's not good enough, especially given the money they've spent bringing players in over that time.