How much does 30+ feet actually effect ability to find space

The answer depends entirely on where you like to camp. Many NPS and FS campgrounds in the West, have mostly tent sites. Trailers under 24 feet usually fit. The older campgrounds barely have room in the west to drive through them with a large rig, much less camp there.

I have run into plenty of campgrounds where there is not enough room for a 24 foot trailer, but many people think their 35 footer "fits everywhere." If your idea of camping is RV parks surrounded by white fiberglass no problem.