At the end of the day I never wanted to waste time boiling water/cooking food I just wanted to eat and sleep. I found myself eating cold even with a stove so I just dropped the stove.
I don't know anyone that has done it just to be hard-core.
True.
There is one interesting exception though: everyone I met who traveled (not hiked per se, but lived out of a backpack), had one "luxury item".
It was something that was absolutely not necessary, but they lugged it around with them anyway, because it made sense strictly for them.
One dude I met had a folding camping chair. (relatively) big, awkward, weighty. But around the campfire, everyone was sitting on rocks like cavemen -- except he was enthroned on his camping chair.
Before you ask: my luxury item was a discman (this dates me, I suppose :-) ), plus a few CDs. Really awkward. Susceptible to impact and moisture, requires batteries, etc etc. But I just love to get lost in rhythm and let it drive my thoughts while I'm out hiking or biking.
There are situations where a tent will be more comfortable: a tent provides protection from the wind absent natural barriers, a tent provides a refuge from biting insects, etc.
In many situations, the comfort provided by a tent is more mental than it is physical. The full enclosure of a tent provides comfort to people who worry about critters crawling over them in the night. Some people just feel more comfortable when fully enclosed.
All this said, it does take more expertise to sleep comfortably with a tarp. Site selection is more important. There are several ways to pitch a tarp and the best pitch to use depends on the situation. Tarps are more fiddly to pitch.
Insect repellent and site selection (don't sleep next to lake) handle low bug pressure situations.
I don't worry about other critters where I hike in the PNW.