Interesting comments, I have never thought photographing anything as "wasteful". To advance as a photographer you need to shoot a lot not worry about the possible photograph "around the bend" so I will pass up photograph what is in front of me. Always carry 2-3 times more film then what you think you will need.
Not having a single care about whether a given composition is truly worth the frame spent to capture it would be lovely. The reality of the matter however is that photography has to exist within a budget, and the priority level given over to my film photography means that its budget isn't exactly sizeable in my case. With digital, it costs me effectively nothing to capture photos, and the difference between taking six shots or six hundred is minuscule at best. But in film? Well, that is a difference of what? $50 or more, plus development...
For a number of shots that I passed up it was because I knew there was a specific location somewhere else that I wanted to photograph. The outing was a quiet little photo walk in the cold, and there was no intention, plan, or any remote desire to be fiddling with swapping film once I left the house. That I could take photos on the little trip was a bonus to the trip, but not the primary goal of it, and having 220 rolls on the market would make my life easier.
But to skip back to the topic of whether taking a given photo is 'wasteful' or not, I would have to say that the bar of what is 'worth the frame' changes with the tools you are using and the costs. If tripping that shutter is going to tie up a lot of money in materials, then most of us are going to be far more careful and take the time to be far more sure of ourselves before letting that shutter open. Then compare that to dealing with all digital gear, where more than once I've gotten into a conversation with someone who was interested in the gear, and the camera has been pointed off into a random direction without thought or care while the shutter is held down for no other reason than to demonstrate the size of the file buffer. The more it directly costs you to press a shutter button, then the higher you raise the bar on what is truly worth a photo. With my digital camera gear I could walk around and snap a photo at every step on one of my walks, assuming I brought along all my largest memory cards, but that bar of 'what is a good photo' is still far higher than that. (There have been dozens of times where I've left the house specifically with the intention of taking photos, but still ended up at home without having snapped a single frame even when it was digital and wouldn't have cost me anything but a moment's time.)
And somewhat on the flip side to the care and caution before taking a photo I have to say that I've found that some photographers gain far too much 'confidence' in their work and build far too high of an opinion in the images they capture. Some of the blandest and most boring photo work I've ever seen was from a rather unfriendly fellow who would make a point of ridiculing myself and a few other sports photographers with claims that he could do in one photo what we took hundreds for, and that we merely 'sprayed and prayed' while machine gunning shots. Seems like it is a fine line to walk and an easy trap to catch yourself in. But I figure that if I ever get to the point that I am pleased with the majority of photos I take, let alone all of them, then I will know I'm doing something 'wrong', as it means I'm no longer expanding and pushing my own boundaries.
But to get back more on topic of hope for 220? I'm sure not holding my breath for something like Delta 100 in 220 rolls priced competitively compared to a pair of rolls of 120, but the market clearly isn't as 'dead' as many here seem to believe given that myself and others still want to buy the stuff for specific projects. Rather it is unprofitable in the eyes of the current players in the market. A rather subtle difference if still extremely important. And it isn't a product you need to truly mass produce and have hundreds of rolls sitting on store shelves in every single city in the world. It is a product that could do just fine run in relatively small batches that are sent in large bulk orders a few times a year to select regional online retailers, and the next batch isn't run till someone rings up and says a regional stash is getting low.
The question is: Which manufacturer and which retailers are willing to team up and solve the problem of production of the stuff?
The only sure fire way to never see a roll of 220 sold at retail is for everyone to stop asking for it to ever be sold at retail again.