Not necessarily so. I have two Nitto stems that give five inches of adjustment. I don't NEED five inches, but it's there if I do. I bought the first one after I started having back problems, and it was so comfortable I got one for another bike.
As to the general question, I've never seen a reason for the general move to threadless. I've ridden at least 60,000 miles with quill stems in the last 40 years, and I've never had nor heard of a problem with them. They work fine, as do threadless. But if you read this forum often, you've certainly seen many discussions of fit where a problem might be solved by moving the bars up or down. With quill stems it takes 12 seconds and it's free. With threadless, you have to flip the stem or buy a new one.