I have one of those, he is 8 now, and his big issue is with texture, it started with baby food, he wouldn't eat anything with a texture to it and he would only eat peas and apple sauce, he did drink a lot of milk to stay full, everything else had to be mixed in to the peas, and with n texture.
I finally had to limit his milk to let him get hungry and I always offered a variety of foods, eventually he found food that he liked better than others, so we focused there and worked out way out from there... but yes the old saying they will eat when they are hungry does work and no it's not cruel, eating is one of the few things kids have control over, and I respect that but we also have to teach them to be risk takers and try new things. Start with what you know will work Yogurt then try apples dipped in yogurt, or peanut butter and yogurt dip with apples or pretzels, then maybe plain yogurt with carrots or celery or with a little turkey slice rolled up, or with grape tomatoes, if it is the texture that is part of the issue then try to find things with similar texture, yogurt is similar to fruit smoothie (with protein powder) or similar to salad dressing for veggies... encourage him to try one bite.
my picky eater surprised me one time when I was going on about some salami that I was eating and he wanted some, I told him he wouldn't like it but he persisted so I gave him some and he loved it... probably because I was going on and on about it made him want to try it, he still loves salami btw, sometimes they want what they cant have...
but I would say that I learned the hard way with my 2nd and third child that too much milk will ruin their eating habits! I didn't take it away completely but I did restrict it till after they ate some of their meal, and none in between meals, but yes it is common!