I've never understood this argument. It's not like the LCD is built to your order -- you are buying something that has already been made. Your buying it consumes no more resources than letting it sit in a warehouse (other than the fuel spent in delivery, I suppose).
If the concept of the individual unit that you bought being built before you bought it doesn't make sense. Consider the unit that gets built and put in the warehouse to replace the one you bought. If you don't buy a unit, then that replacement unit never gets built. It works out to the same thing. (Or, consider in aggregate - if nobody buys them, they aren't going to keep making them. It's not like you can't make punch cards (or 5.25" floppy disks, CRTs, 8-track tapes, whatever) anymore, but if nobody buys them, who would bother to make 'em. That is the limiting case, but that limiting case is made up of a whole bunch of individuals not buying.)
Or maybe you believe in some sort of a cargo cult? LCDs just materialize in warehouses, and if we didn't buy them, the warehouses would fill up.
In that case I suppose we would be doing the stores a favor by going in and stealing LCDs to get them some more warehouse space. (After all, don't want them to have to deal with storing all that nasty money that keeps building up either.
Well, Sorry Virginia, there is no Santaclause.
Meanwhile, your old CRT will die someday and there is no guaranty that there will be a more efficient way of disposing of it a few years down the road than there is now.
I don't know much about future disposal tech. What I was mentioning in savings was that the LCD you buy a few years from now is quite likely to be better and more efficient than the one you get today.
LCD tech has been evolving rapidly over the last few years - generally getting better (faster response, better brightness range, larger sizes available).
In addition, we are just starting to see LCDs with LED backlights - which are more energy efficient, no mercury, LEDs generally last longer than florescent tubes (although that may depend on cooling efficiency/etc.)
Since this tech is becoming available now, it doesn't take much of a crystal ball to suggest that it will probably become cheaper/better/more available over the next few years.
As to disposal - a few years ago the matter of disposing of CRTs wasn't much talked about. (Could dump them in the trash even.) Now, many places they are being collected for recycling. So there has been some progress in that area. I am not up on that end of things to know what advances might be in the wings.
Even if more efficient tech isn't on the horizon, by waiting to buy the item you have still slowed the rate of energy and resource use. (Eventually the Sun's hydrogen fuel will be depleted, it will swell up and the Earth will be toast. But just because that will happen sometime doesn't mean it is desirable to have it happen right away. Sometimes delayed fulfillment is a good thing.)