It totally depends on where you hike. If you're in a place where you're more likely to camp in established sites, sometimes those sites aren't big enough for a large shelter. Sometimes the person with the large shelter squeezes other group members into less ideal, but doable sites. In some regions (the pacific northwest comes to mind) shelter sites can be hard to find because there is so much ground cover. You simply can't pitch a tent on endless expanses of huckleberry bushes. Many places this isn't much of a concern though.
Floorless shelters are indeed better because of the reason that you state.
One way that I deal with this is that I'm fit, and I keep hiking. I've run in to situations where I just need to keep putting in miles, even when I don't want to, because there is nowhere to camp. Look at maps, it can help. Camp near water, people have usually found a place to camp near there before. Having an oversized shelter will mean that you can't camp in the same places as someone who has a bivy. Please don't rip up shrubs or level sites permanently to camp in a spot. I also sometimes just drape a tent over myself if I'm dealing with a drizzle.