I don't think "relentless attack" is necessarily the best way to win football matches.
Before I continue that thought, a couple of things about "3 points for a win" - the idea behind awarding 3 points for a win rather than 2 as it used to be, was to encourage attacking play, but mainly to reduce the number of draws.
While "attacking play" is subjective, the number of draws didn't dramatically drop in the long-term as a consequence. I read something about this somewhere that said various things had been tried in different leagues to reduce the number of draws, none of which had been particularly successful. (Think there was even one league in the USSR where only the official state club got a point for a draw!)
But those two thing "attacking play" and "reducing draws" don't always go together. Both sides going hell for leather can end up in a 3-3, while two cagey teams can still easily end up with a 1-0 scoreline.
So "relentless attack" - it sounds good, doesn't it? Wave after wave charging forwards at the opposition goal. Problem is, well-drilled defensive sides, such as we've struggled against for donkey's years, can sit back and take that sort of thing all day. They don't need to move as much as the attacking team, so they tire less quickly, and come the end of the game, they can skip out of their own half and nick it with one down the far end. We've seen it happen far too many times.
So we don't need to constantly attack, it puts the other team on alert, simplifies the game for them and generally means relying on a piece of exceptional individual skill or an accidental mix up by the defence.
What about possession, then? Again, sounds good. Keep the ball and they can't score. True. But if we're in possession, they are freer to pick out runners, organise marking, and generally go about the business of defending their goal without having to worry about all that ball-control and technique and skill stuff that you pay so much for.
What you really need to win games of football is not all-out attacking for 90 minutes, or 80% possession. What you need is to have a simple, effective way of moving the ball when you do have it, and when the opportunity is there. And if the opportunity isn't there, you build for it.
That means sometimes you play the ball around on the half-way line and let your wide men lose their full-backs so you can release them with a quick diagonal ball. It means sometimes, you give it back to the keeper to stretch their midfield and forward line and create a bit of space. It means you tease them into your half, even let them have a bit of a run at you, so when you take the ball away from them, they are still moving towards your goal-line, even though you, and the ball, are now going the other way.