Don't think you can compare Koeman to Mike Walker tbh. Martinez is an apt comparison to Walker, and many knowledgable Blues made that comparison at the time - two men who just lack basic comprehension of football management. At least Walker had the honesty to be completely over-awed by the job, whereas Martinez was far more insidious.
I get the impression with Koeman that he actually does know the game inside out, it's more of an issue with his man management - he can't communicate to the players in a way that works. Actually takes some skill to make seasoned internationals looks as clueless as this Everton side does.
I say 'get the impression' because bottom line, when things are as badly pear-shaped as they are, we all start projecting negative pictures onto the manager - he's a tyrant, he doesn't get Everton, he's more motivated by his golf handicap etc etc. There's no real evidence for any of it - it just feels like it should be true given how bad things are!
Martinez was a nice guy but obviously out of his depth, that was his one saving grace. Koeman is not remotely likeable. While he isn't necessarily distracted by the golf course (or his skip hire business!), the whole Burnley game stank of
"we've had enough of our manager, and we can't be bothered playing for the shirt, because our agents will wangle a move to another top side when Everton drop." or "I can't be bothered because I'm retiring soon". Makes me sick, honestly.
Earlier in this thread, I named a pacy 4-3-3 XI that would die for the shirt under Unsworth. After Leicester won the title, I believe that it all boils down to motivation, nothing else. Yes, money helps, unquestionably, but unless City are secretly investing in Brazilian cyborgs named after a very naughty boy, that can run like the T-1000, then it's just 11 humans against another.
It doesn't matter if you are Lionel Messi or Lionel Richie, if you can't get the ball, YOU CAN'T FRIGGING WIN!!! Just ask AC Milan in the first half of the 1990s or Dynamo Kiev under Maslov. Get in their faces, frustrate them, use the opposition's desperation against them - because that's what Burnley did to us. We have the players to do that, but the 20m+ layabouts we signed are NOT players of such ilk!
Finally, and I know this point needs no further elaboration but WHYYYYYY is Martina actually still playing!!!?? Might be a good idea to keep mentioning it, just in case anyone forgets how much of an actual turd he is.