It’s both, I think. There’s definitely a lot more looseness in what’s allowed now compared to fifty years ago-- as long as you’ve taken a dribble and keep moving, you can pretty much pick up the ball, take three steps in any direction or combination of directions, and as long as you get rid of the ball in some way at the end of that, you’re fine. And in practice, often four steps is quite possible. NBA referees really, really, don’t like calling traveling on someone who’s moving and taking a shot. (you can still get called for travelling on a slow post-up move).
So it is looser. But, the players are also really really good at using those three steps. Often I’ll find myself screaming at the TV about a travel, and upon rewinding see that it actually wasn’t one (by current standards) – the player got the ball off before the fourth step; they were just so good at using them it seemed like they must have traveled.