The sad situation of adjuncts

This adjunct situation is a real disgrace. I just read this piece in Salon.com, and it made my stomach turn. These are people who often have the same training and qualifications as full-time faculty at their same university, and yet they are paid a fraction of full-time salary. 
No tenure-track faculty would accept the frequent working conditions that adjuncts endure: not knowing which or how many classes they will teach, being dropped into courses at the last minute, zero or little support for professional development from their institutions, teaching the odd-meeting time courses only (weekends, nights). I would be howling about those conditions. At least I would be getting paid a reasonable wage for it.
Part of my displeasure about this is the real feeling that I easily could have been in their situation. I was lucky to get a tenure-track job, but it wasn't like I had multiple offers. Jobs in my area are scarce and there are too many PhDs out there looking for them. I am so thankful that I have my job (and tenure). I worked hard to get it and to keep it; but it's not clear to me how I am that much different from many of the adjuncts we employ. Or at least I wasn't that different when I just got out of grad school.
This seems analogous to the minimum wage. Before then employers could get workers for a seriously low wage. Those people didn't have to take those low-paying jobs, they chose to. But at some point we as a society decided it wasn't right to pay workers so poorly, and decided that we would set a minimum wage. Whatever you think about where the minimum wage is now (too low, too high), the idea was that even if you could get people to work for a lower wage, it wasn't acceptable to do so. Might we need a minimum wage for adjuncts? How much do we value the job they are doing? Maybe we get what we pay for. This reminds me of descriptions of teachers in Finland -- their pay is higher, and they have lots of competition for teaching jobs, meaning they get great teachers. I don't mean to denigrate adjuncts, because they are typically dedicated and good at what they do. But what if the adjunct wage was higher? Would we or could we get higher quality instruction from them?
Of course this comes back to money, always money. Universities don't have the money to pay faculty what they deserve, much less the adjuncts. As long as money is as tight as it is, we'll have to use adjuncts because we don't have the money for additional faculty jobs, and as long as we can find people willing to take the job for these low wages we will do it. We don't have a lot of choice, I guess.
Maybe adjuncts should form a union.