I have alot of sympathy for that reasoning.
Here's a suggestion..
Instead of you alone taking on the burden of telling people to quote better..
How about we as a community criticise bad netiquette as it appears (and even in a FAQ. - i'm sure shlomo you're familiar with usenet "where" similar articles on how to quote are written all over the web)
But we have to be consistent..
A big problem along the lines of posts taking up FAR too much space, are people who have HUGE signatures.
A thread of 3 pages becomes 15 pages.
It was far worse when Yaakov used to post here continuously, each post with a huge picture in the signature.
For a start, I suggest that moderators, to set an example, shouldn't have huge pics in their sig..
And nobody should..
And it should be understood that these things make posts take up unnecessary space, and threads unnecessarily long.
I can tell, from the big signatures, that we have alot of people here that don't have a natural clue. They naturally do not get it. They are naturally technically inept..
Nevertheless, even an old man that is completely computer illiterate, can be shown how to use a computer. Similarly, these people can be made to understand that a big signature is unnecessary, and the problem of it.
I am actually very pleased to hear that you shlomo also feel that threads were unnecessary long (your reason bad quoting.. But no doubt big signatures would factor into that too, it's the same concept).
If the moderators quote properly, and police it, it can be done easily..
The moderators here are very dedicated and do a fantastic job.. It's really no big deal for them and the rest of the JTF community, including myself, to correct people and tell them they are overquoting or their sig is too big.