Think about it this way:
How hard is it to volley? Not very, most people can volley the first time they ever play tennis. All you're doing is hitting a ball before it bounces.
How hard is it to hit a forehand? A little bit more tricky. You need proper positioning, stroke mechanics, timing, and confidence to round it all out. Along side a ton of other things.
It just takes a bit of practice, and I would know! I started out as a S&V guy, now I am an aggressive baseliner. It took me about 2-3 years of quite hard work to get where I am now, and even then I'm not really an amazing baseliner.