There's a reason they are more stable James - they are able to sell their best players season-after-season, change managers regularly yet still perform, whereas we lose a few players to injury and capitulate. The reason they are 'stable' is because they 100% back their model which typically has a well-respected Director of Football who initiates and manages the long term plan irrespective of the manager or players they have and seemingly with a much lower spend than others. Their recruitment model's are incredibly good - they have the ability to identify emerging talent before it becomes excessively priced, which they then nurture for a season or two before selling at very high profit margins - and they have the foresight to have their replacements identified and signed prior to it. They hire progressive managers, and allow/encourage those manager's to regularly play new players irrespective of age and with zero experience of the Premier League.
Admittedly, there appears less pressure on them than there is at Everton, but could you honestly imagine us hiring Iraola, Andrews or Hurzoeler before they hit this league like these three clubs have, or committing to putting faith in their data-based approach to finding gems like Caecedo, Mitzuma, Thiago, MBuemo, Wissa, Semenyo etc?
If the model is flawed, or you don't have a model then how do you get sustainable improvement? Our model has appeared to be hire a 'tried and trusted' old school manager ( Moyes, Allardyce, Benitez, Scotch Egg) as we've panicked after having a good one leave (Carlo) or be sacked (Silva...and possibly Lampard).
I think that's why "the bedsheets come out" more often at Everton.