does it have to be? until a more modern blitzkrieg and pressing game came about everyone carried on same way, England have the players to play a more modern approach it is just Southgate isn't a modern approach manager maybe the reason it is "pedestrian" isn't that it has to be but that managers are worried if you push and attack you'll get hit on the counter so not the way football is but the mindset of some managers
England have the players to play a more modern approach, but they do not have the time together, which is why all the top nations are in the same boat. Its not about individual ability, its a lack of systematic cohesion. Look how long it can take new signings to bed into systems at clubs, thats with training every day, national teams do not have that luxury. The tempo of the game is down to both teams, and more often than not for the top end nations its either a game against lesser quality opposition in a low block just frustrating you to keep the score down, or if against another quality side its likely to be cagey, especially in the first half of games where the tempo is usually set. You can't just switch the speed of play on and off like a light switch. England have been hit on the counter plenty in recent times, so we do push bodies up, but thats completely unrelated to the tempo of our play. I'm sure every manager on the national scene would sooner choose to be more penetrative on each attack than recycling waiting for an opening, but its not a choice.
The Spanish national side played lovely football at the time, they didn't spend all the time in the world honing it. They dominated football for 4-6 years. You could argue they were aided by a large part of the side playing at the same 2 clubs. But I don't think you need to be as brilliant as those sides were to win the Euros this year. You certainly don't need to have been that brilliant to have beaten Croatia in 2018 or Italy in 2021 or France in 2022.
Spain were an exception to the rule, and as you've already said, they were predominantly playing together regularly at club level. Before then I can't think of anyone else playing a natural free flowing game since Brazil in the 90s, and International football was on a much more even parallel to club football back then, clubs football has just progressed tactically to another universe now.
It's because club football is Harlem Globetrotters now and has been for a while. It's All Stars football, the top teams can pick the best players for any position from any country in the world and have them all together in the same team. International football is limited to the best players from an individual country with no option to draft people in from elsewhere to fill the weak spots and they inevitably leads to international football generally being of a lower quality to top club football. In the past national leagues were mostly full of players from their own country so international football used to be regarded as elite because it was the pick of the best players from each country. And in general the run of the mill club players in each country were of a lower standard than the ones playing for the national team. Now that club football is so international even below the top divisions, everything has changed.
From midfield up we are very much Harlem Globetrotters. And at rightback, with about 4 million options. The defence and GK aren't of course, but that's the only area Southgate needs to earn his bread really, and he doesn't.