LOL...

How much hardware do you have to replace on a 2000 era Abacus to be able to run all the current OS (and be functionally as good as a 2009 Abacus)?

Way I looked at some of the hardware upgrade prices a while ago, it was easily as much as the difference between trading up to newer models of closed arrangers if you got a reasonable price for the old model. Not to mention all the additional money you have to put into VSTi's to get a sound that is superior to a TOTL closed arranger. Oh, and we still haven't forgotten the base price of an Abacus, which makes an Audya seem like a PSR

You can trade up to newer Tyros's for YEARS (decades) before you have outlayed a total greater than purchasing an Abacus in the first place, never mind all those VSTi's (the GOOD ones cost real money!).