What do you THINK you're going to do with all those CDs? You're going to listen to them. And they're two-channel. As long as you listen to them, two-channel will live.
You also seem to be worried that in a couple of years, the only things you'll be able to buy will be multichannel something-or-others. But multichannel something-or-others will always be able to play two-channel, for all those boom boxes and Walkmen and such, so you're not going to be shut out of new music. And the odds are CDs will continue to be the primary music medium for years to come. Stop fretting.
You also seem to be worried that in a couple of years, the only things you'll be able to buy will be multichannel something-or-others. But multichannel something-or-others will always be able to play two-channel, for all those boom boxes and Walkmen and such, so you're not going to be shut out of new music. And the odds are CDs will continue to be the primary music medium for years to come. Stop fretting.