I'm blocked from youtube right now NZA, but there are plenty of people that do. Linguini has done it since the old days. I've had people to it to me in chicago. The thing about competitive play is that if its possible to do something to win, somebody will do it, and then somebody will copy them.
Everything should not have the same difficulty to perform. The metagame advances because certain things are very good for how easy they are, and those things win until people get more consistent with the harder things that are more effective. The fact that there is counter play means that it is balanced; whether or not a player is good enough to actually execute properly is an entirely different story.
And your ike parallel is flawed. I actually give a specific and universal escape from shield pressure, while you just say "don't get hit" (which means nothing).
Maybe against bad players... To good players the game is about maintaining advantaged position much more than executing combos or whatever. Landing a shield grab means that your opponent went from being advantaged to disadvantaged, even if it was just a split second, and you capitalized. A good player will never get shield grabbed because they will not be so foolish to take the risk (unless they are attempting some yomi).
Read Little England's
10,000 words of power, he has a section about not attacking from a defensive position which will probably explain it better than I could.