The Key To Staying Current Is To Sell Your Mac Each Time New Ones Ship
It will only cost you a few hundred dollars each time if you sell your Mac and buy the new one each time they ship. Hanging on to a particular unit for longer than its current reign is why most of you find yourselves in this pickle now.
Each new OS is built to take advantage of the newest hardware with future hardware plans in mind as well. I think Apple does a great job of providing as much legacy support as they possibly can under these constraints.
I understand how easy it is to become attached to a particular unit. But you have to discipline yourself to sell each time and you will then either perhaps make a profit, lose no money or only have to spend a few hundred more to advance to the next level. I bought and sold 4 different G5 PowerMacs during that era - the last being a 2GHz DC just now for a $275 profit. I sold a dual 2.5 G5 PM for $2500 20 months ago after the Intel era had already begun in February 2006 when the October 2005 Quad G5 was already only $2699 refurbished.
You just have to discipline yourselves to let go each time and move on up to the next great Mac. You may also want to notice that the current line always goes refurbished within only a couple of months at most and that is a way you can sell and buy for almost no money at all. Refurbished Macs are indistinguishable from new ones and carry the exact same warranty as new ones. Even if something is wrong with one, Apple fixes it for free right away.
So the whining here is all about you who did not sell out of date Macs as soon as they became outdated. I understand that there are issues with some software and hardware not translating to the next great Mac right away or in fact never. But there are still ways to advance as soon as possible without taking a financial bath by waiting longer than you need to.
Tiger is an awesome system and will serve legacy systems well. There are work arounds to get Leopard running on all G4 and even G3 Macs. So all is not lost. But please give Apple a break when you are really complaining about your inaction over years of opportunities to roll over your gear.

It will only cost you a few hundred dollars each time if you sell your Mac and buy the new one each time they ship. Hanging on to a particular unit for longer than its current reign is why most of you find yourselves in this pickle now.
Each new OS is built to take advantage of the newest hardware with future hardware plans in mind as well. I think Apple does a great job of providing as much legacy support as they possibly can under these constraints.
I understand how easy it is to become attached to a particular unit. But you have to discipline yourself to sell each time and you will then either perhaps make a profit, lose no money or only have to spend a few hundred more to advance to the next level. I bought and sold 4 different G5 PowerMacs during that era - the last being a 2GHz DC just now for a $275 profit. I sold a dual 2.5 G5 PM for $2500 20 months ago after the Intel era had already begun in February 2006 when the October 2005 Quad G5 was already only $2699 refurbished.
You just have to discipline yourselves to let go each time and move on up to the next great Mac. You may also want to notice that the current line always goes refurbished within only a couple of months at most and that is a way you can sell and buy for almost no money at all. Refurbished Macs are indistinguishable from new ones and carry the exact same warranty as new ones. Even if something is wrong with one, Apple fixes it for free right away.
So the whining here is all about you who did not sell out of date Macs as soon as they became outdated. I understand that there are issues with some software and hardware not translating to the next great Mac right away or in fact never. But there are still ways to advance as soon as possible without taking a financial bath by waiting longer than you need to.
Tiger is an awesome system and will serve legacy systems well. There are work arounds to get Leopard running on all G4 and even G3 Macs. So all is not lost. But please give Apple a break when you are really complaining about your inaction over years of opportunities to roll over your gear.