I just had to respond to this - DS is almost FIVE and is 90% daytime potty trained. It has been a Long Hard road but we are almost 100% there! We started at 3.5, it would have been sooner but ds was extremely resistant and then we moved so we waited until the end of the school year.
The ONLY thing that worked for us (outside of not ever using Pullups during the daytime) was basically learning to accept it. Nothing I did ever made the slightest bit of difference except to make it worse if I got upset. If I praised, it made no difference. If I bribed with trinkets, candy, anything it worked for awhile but it did not train, he would pee/poop for the reward and then go back to doing it in his underwear.
Yes there were times that I lost my patience, but only a very few times let it show. Yes, us moms should be sainted!! We made it though, I still need to remind for pooping, I just emphasize at the time that he usually goes that he needs to 'try'. I hate nagging him, but I ask him to 'try' and usually he'll go, and this has led him to recognize what it feels like when he needs to go, so I don't think telling/asking is a bad thing. I remember my mom telling me 'I' myself needed to try when I was little, now this was 40 years ago and I still remember it so it had to be when I was 4 or so...and I was considered potty trained at 18 mos. so I don't think asking them to try is considered not potty trained.
Hang in there, it will come

But it took us Forever and it was very very gradual, where it came down to a few days ago I realized he hadn't had any accidents in awhile now. What a wonderful realization!!!