I haven't been to Phuket for a while but that is one thing I really hated about the place and this is nothing new. I recall being on the beach in Kata or Karon and it was just a line of sales people the entire time I was there. This made me nervous about leaving any valuables on the beach to go for a swim as well.
In Da Nang, "traveling sales reps" are banned from the beach. Every now and then someone gets bold and does it anyway but they are quickly apprehended by security who take their photo and tell them to bugger off. This does make the beach experience a lot better.
There are a lot of beach areas all over the world and mostly in rather poor countries where touts on the beach is just the norm. I was once visiting a friend in the Caribbean and there must have been 20 dudes who walked up playing guitar without being asked to and they just keep playing until you give them a bit of money to get lost. It really does ruin the ambiance. When I was in Mexico entire brass bands would pull up doing the same thing. It makes me want to not go there.
RE: Popular Thai beach areas becoming a real hassle after drop in tourism numbers