I don't think they have declined - they just can't stick around and defend like they used to because the type of attack has greatly changed.
Very few attackers are like Drogba or even Lewandowski anymore who go toe to toe with central defenders.
Ronaldo changed the game and made team's most deadly attackers come out from wide which meant that Central defenders had to come out of their positions with pace and read the game from that area.
Messi changed the game with the false 9 role where he would almost find clear space in front of the central defence to bring them out centrally to take them on directly or play the inverted forwards in behind.
Then possession football meant that attackers started playing in tip tap triangles much more so defenders had to again wait much more and defend as a unit to take down a team attack than a single defender stopping a single attacker like the Brazilian Ronaldo or Henry. Not only that - it meant that defenders also needed to be just as good at initiating a quick counterattacking pass or breaking away from a high press because chances became minimal.
The thing is - we can talk about Messi, Cristiano Ronaldo, Pep's Barcelona and how they were so good - but many teams big and small use parts of these tactics now and the game evolved 5-10 years ago. In the Premier League alone only Burnley play old school classic football with crossing and target men.Football isn't played nor do strikers attack the way defenders like Stam or Maldini constantly dealt with.
Back during the wonderful Milan defence period - attackers used to play Central cutting through balls, balls over the top, big wide crosses - that hardly happens anymore. Teams like to literally open up the team to absolute pieces with passing, dribbling and possession before tapping the ball in to the net - passing the ball or crossing it how it was used to is deemed as giving the opportunity for the opposition the chance to get the ball and attack themselves.
Van Dijk has been the best for the last 2 years & there's no shame in admitting it even if it's Liverpool as a team that have a good defensive work ethic.
I dunno, to me the idea that defenders like Ferdinand, Vidic, Campbell, Adams, Terry, Carvalho, Carragher, Hyypia, King etc would struggle in the modern day Premier League astounds me.
I don’t really see the idea that defenders have to defend differently to how they used to.
I mean you only have to look at the majority of goals City and Liverpool score(more so Liverpool) to see that crossing football is still dominant. This idea that all teams are passing through defences, hogging possession, dribbling and playing triangles is not the actual reality.
And even going back to early noughties, you had the Milan side under Ancelotti who very much played through the middle. Kaka, Rui Costa , Seedorf, they never even played with wingers. The Real Madrid team of that era that utilised Zidane as a wide playmaker, with Raul pulling out wide. Arsenal didn’t play with crossing wingers, Pires cut inside, Ljungberg was essentially a wide poacher and Henry pulled out wide, centre backs had to deal with that for years.
A lot of these teams are scoring goals like this because defenders don’t seem to want to defend. Defending your box by doing simple things like heading, anticipating and marking. Basic defensive principles that a lot of centre backs seem to lack. Watch big games nowadays compared to the old days, they are full of catastrophic defensive mistakes. Is that because attackers and attacking football is that much better? I don’t think so. All those ridiculous comebacks, look at Liverpool’s goals against Barcelona, it was comical, basic defending not being done. Liverpool and City are capitalising in this era of defenders not wanting to defend. So they overload wide areas and fizz balls into the box over and over because they have good attackers and they know defenders don’t defend.
Also disagree that there are fewer Drogbas and Lewandowski around. Because city and Liverpool don’t have them doesn’t mean they aren’t around. There are still plenty of physically imposing penalty box strikers around, Lukaku, Cavani, Abraham, Dzeko, Piatek Aubemyang etc. Even in the PL, you have Wesley, Haller, Gimenez, Vardy.
I completely agree that Ronaldo and Messi have changed the way wide forwards play but I don’t think it’s meant the dying of the traditional centre forward. All it is is that teams now play with one instead of two.