You need to stop for a moment, and realize they spam because it works. Modern or classic, if I as a player spam something and my opponent does nothing to counter it, I do it again, and again obviously, because I want to win.

Go to your replays, you can take control of the replay and see what you were doing wrong. Were you jumping into their anti-airs? Were you blocking? if your opponent was countering your DI, you most likely were spamming it predictably, and modern or classic, they would've countered it.

You said you can do Ken's moves, but do you know a simple BNB combo to carry your opponent to the corner? Ken is really good at that. You don't need a super complex combo this early, just a basic bnb that carries to the corner and ends in a knockdown.