Football has definitely changed. In the 2007-08 season Del Piero became Serie A's topscorer and at the time it was seen as absolutely incredible for his age, which was 33.
At 33 players are no spring chickens today either, but there are so many older players right now killing it (Benzema, Modric, Messi, ..) or still active at a very decent level (Thiago Silva, Giroud, Lloris, ...).