Considering that they have both always had it, it's not that hard to imagine... and it's seven years since they got physical Water STAB too...
I see your point, though. R/S were a little hampered by some Pokémon having good stats at the wrong end of the spectrum. Crawdaunt sticks out as a prime example. Unfortunately, others, most notably Sceptile, suddenly became an example of the opposite. Sceptile was given a Special Attack stat suited for all those Grass moves it learnt back then, but now its level-up movepool consists almost entirely of Physical moves (Absorb and Leaf Storm being the exceptions).
Another often-cited complaint of R/S was that most available Pokémon during the story were quite poor battlers. NU frequenters all over the board, with bad stats and movepools. There were some okay-ish 'mons in there, but also a lot of bottom-of-the-barrel scrapers. You were treated with the likes of Shroomish, Makuhita, Electrike and Volbeat, back when those 'mons had half as many available moves as they do today. Most players I knew wound up with a Kadabra on their team, because it was comparatively so much stronger than anything else that was available. Emerald remedied the Pokémon selection a little, but Sturgeon's Law was still very much in effect.
Now, a few generations later, I'm looking forward to try again. With the Physical/Special split and movepools growing into the heavens, the multitude of poor Pokémon in RSE have gotten a much better arsenal to play with. Using Roselia, for instance, is a lot more fun now that it gets a better Grass move than Magical Leaf, and has an evolution that lets it perform in the late-game as well. Crawdaunt can finally put that great Attack to use. And I'm getting a Kadabra just for good ol' days' sake.