REmastered classic CD's

Can some one brieflt explain why many of the newly remasterd CD's sound so much better than the originals. Many say they are using 20 (or higher) bit technology. But we're still listening with 16/44 equipment. I'm not complaining , mind you, I love the changes! Some of the better producers of the 70's like Bill Smlyzck (sp) of Eagles fame did some nice studio work for bands like the Eagles and James Gang. so what does the new re-mastering do?
I have bought a ton of remasters over the past few years and I still am amazed at how much better most of these sound. The best way to explain why there is a difference is just plain taking the time to do it right and much better analog to digital conversions. As you probably know most of the early cd's were just copies of the tapes that they used to press the regular vinyl lp's. Most of these tapes were not the original master tapes, but were usually several generations down the chain with all sorts of funny eq'ing, compressing, etc. to make them sound ok to the average person or over the radio. I would like to think that small audiophile labels and other companies such as Mobile Fidelity and DCC made more people aware of what was actually capapble with the cd format. I think that enough money was going to these labels that the big guys finally got the hint that it was money out of their pockets unless they changed. Of course going back to the original master tapes removes layers of sonic crud and gets you the best source there is instead of a copy of a copy of a copy ... Technology also plays a big part because now there are A-D convertors that are light years better than those of just a few years ago. Being able to convert analog to digital at higher sampling rates and more bits gets the transfer that much closer to the original so that when they do the final 44.1/16 transfer it sounds that much better. Also noise shaping techniques such as HDCD, SBM, Apogee's UV22, etc. allow you to hear what is closer to 20 bits of resolution. Hopefully the record companies will get off their butts and start putting out some DVD-A's soon!
I have been buying classical CD's for $2.99 at a local closeout chain called Pic n' Save. They are 20 bit digital recordings mastered via 32 bit sound processing. Most are done in England and are performed by the Danish Royal Orchestra. They are distributed by The International Music Company, Hamburg, Germany. I do not know if these qualify a specialy recorded/engineered disks, but they sure do sound a lot better than my regular much more expensive classical CD's. I play them on an old CAL player that I believe has an 18 bit converter. I also have some MFSL CD's and enjoy their smoothness but do not like the low (in comparison to my regular CD's) recording level. Ry Cooder I have noticed seems to have very high quality engineering work done on his CD's, though I don't see that they are recorded in any special manner. Elton John's CD's seem to be some of the worst engineered CD's that I own and he's a perfectionist. Go figure. I would like to have a better understanding of the new to be formats, but have been too lazy to study the subject. It would be nice to know which type of transports will become obsolete.