Airlines have been sneaking in newer lower tier ticket levels that exclude any sort of refunds or changes. You probably don't run into these through corporate travel, but if you have a basic fare your ticket is use it or lose it.
Yes, true, but those have all come online within the past 6 months or so (led, I think, by United, and then quickly copied by the other major carriers), and are still relatively rare even for leisure travel, at least in my experience. Unfortunately, I fear that you are right that they will take over the lowest end of the market.
I can't/won't book these for leisure travel, because they don't even allow you to sit with your family members.
Honestly, the recent penetration of basic economy into the US market is something I'm much more concerned about than involuntary bumping. If the airlines are successful, then they're just going to re-set the baseline for standard economy up by $100 or so a ticket. Planes were already full, it's not like they are going to increase revenue by offering cheaper tickets, they're just going to get away by giving you less for your money.
I agree, and I never said differently. Almost all US tickets are non-refundable, and have been forever. Likewise, almost all US tickets are changeable FOR A FEE, which I said pretty high up in the thread -- and the airlines are pretty flexible on what constitutes a change (you can pretty much book a new ticket for yourself within a year, after they deduct the fee).
