RR, you're not the only one who's noticed that, but it's been going on for some time.
It used to amuse me watching little kids' games on Highams' where all 20 outfield players would run around the pitch like a swarm of bees, with the ball in the middle, never being kicked more than five yards. That was because those tots couldn't kick the ball further than five yards.
But why it always happens in the professional game is a puzzle. Maybe the fact you note that teams like Chelsea do it is the reason they all do it?
I've often thought that, if a team practiced it, the keeper could slice or shank his kick into the empty space in the opposite side of the pitch and the corresponding winger would know to run into that space, leaving his defender still in the wrong half of the pitch.
There's a similar puzzle with defending corners. If all 11 players defend, the attackers will leave one player on the half way line, giving the defenders a numerical advantage in their penalty area of 2. But if the defenders leave one forward on the half-way line, the team taking the corner will mark him with two players. Giving the defenders a numerical advantage of....2. Leave two on the half-way line and there'll be at least three of the 'attacking' team kept back to mark them. Leaving those defending the corner with a numerical advantage of....2.