Two things.
1. There is no place on earth where a man can be 6'5, 260 pounds with less than 10% body fat and not be considered big and tough.
2. TEs transitioning to OT was never common, but even when it was less rare, it was because OTs could be 6'2- 6'4 and weigh 285-295. That's a huge difference from now where 6'4 315 pound Michael Oher is viewed as undersized.