Dude, on Black and White (the games I most easily completed) I usually took 16-20 hours to beat the E4. But I didn't explore or anything in that time, just trained my team to an efficient level.
I believe I beat Johto E4 in 30 hours (less Pokemon to train against than in Black/White so leveling is slower) but it could be more or less.
I got lost in the snowy regions in Sinnoh and trained a couple Pokemon from Lvl. 1, so it probably took longer than Johto to beat the E4 but I don't remember.
So I'm not voting, it never ever took me 70 hours to beat the E4.