This is probably a stupid question (I am only a recent convert to the round ball game) but why don't the best players get "tagged" so it reduces their influence on games?

Sometimes they do get "tagged " or kept on a short leash . Ie look at what Carlos went thru against au in the gf where Jonas salley Kept him at a arms length

For whatever reason, it's a tactic that isn't used at pro-level anymore really. Very, very common in amatuer park football, but rare in pro football.

I think it's just seen as negative and not a good use of a player.

Due to the fact you keep in player in check another couple will tup you into shreds .

In the old days skilful were regularly taken out by dirty defenders. What happened to Maradona in Spain was a disgrace.

These days there is far more protection for skilful players than there used to be.

It's because the focus nowadays is more on zonal defence. In the old days, and in amateur leagues like EG has pointed out, man-marking was more of a thing. Now, just say you have an opposition player who plays #10, the team is more likely to drop a midfielder to a deeper position than to just say "man-mark him".

I'll also add that treatment ADP and Juninho copped was a disgrace, it's hardly over.

And heck, Muscat, Savage and Wise had long careers despite being little more than thugs.

Man marking is less useful in football because of the way the defender wins the ball from the opposition.

When the marked player is about to receive a pass, the manmarker can either stand between him and the ball (hence losing sight of the marked player allowing him to get free) or get in a position where the manmarker can see both opponent and ball (making an intercept very difficult as the marker is further from the ball than the marked player). Either way a well struck pass will reach the marked player.

In the codes where you win the ball by manhandling the opponent it doesn't matter if the marked player receives the ball as you can grab any part of the person to stop them.

In football when the marked 'special' player gets the ball there is an immediate problem for a closely placed manmarker. the skilful player is now able to enter a duel of skill with the marker. The marker will nearly always lose unless he has a second defender to support him.

So, for effective man marking, you need two man markers on a single skilful opponent. Once you do that the gaps start appearing all over the pitch for the defensive team.