If Klopp stays still with Liverpool for 5 years, will you want him out even though he's a good manager and plays good football? Its a tough decision. Say next season, you finish 5th, win a league cup and get knocked out in the last 8, will you stand by him?
As I said, it's about progress. If after 4 seasons we're still hovering in the same position and there's no sign that we're getting nearer to the top then fans will want a change. That's not to mean he'd have done a bad job. Discounting another Leicester scenario, we're still in a position now where Liverpool (or Arsenal) have 5 other sides that in any season could finish above them. All 6 sides can't qualify for the CL let alone finish 1st - you have to look a bit deeper and ask yourself whether things are improving and if not, will they in the future.
How is that any different to Liverpool, who have managed to be completely mediocre while playing the manager merry go round for years and years? I'd rather Arsenal's last 20 years and where we are at the mo over Liverpool any day.
Why are you being so defensive?
If you read through my posts regarding Liverpool over the last 7 years or so you'll see I've been more critical of our club than anybody. Chopping and changing every 5 minutes most certainly isn't the answer but there's a huge jump from that to the situation at Arsenal. If Wenger had been at the club 2 seasons and there were signs that things were moving forwards then great. Can any Arsenal supporter say there's been progress at Arsenal in the past 10 years though? Looking from the outside I don't see it.
As I said, Arsenal haven't underperformed in any given season over those 10 years - they've always finished in the position they've supposed to be, give or take. The problem is that nothing is changing, there's no signs of progress and it's difficult to see if how things will improve under Wenger. If Arsenal fans are happy to finish between 5th-2nd every season, get to the last 16 of the CL and win a domestic cup every few years then fair enough but the growing unrest suggests they're not.
Two seasons ago you finished above Spurs but the general feeling was Spurs had the better season, why? It wasn't just because Spurs have fewer resources, it was because there was clear progress from Spurs. They were building a side and things were improving. Arsenal was the same old Arsenal, they'll threaten to challenge and then when it counts they'll fall away only to come back strong in the final weeks, when it's too little too late.