Because, if I want a high end device that will last me 2+ years, I need an LTE one whether I get LTE or not. Your thought had been mine when I got my first phone, the Hero, instead of the EVO. It worked great for the first year, but in this last year I've been having all sorts of problems due to hardware being outdated.
Can you suggest any other device with specs similar to/better then the Nexus Galaxy that doesn't have LTE (or WiMax, since that isn't in my area and never will be now)? The two other phones I'm looking at are the Nexus S, but since the Nexus Prime isn't getting an ICS update the S may not get an Android 5.0 update next year whereas the Nexus Galaxy will, and the Galaxy 2S but the lack of an NFC radio on the Sprint version puts me off a bit. And both of those are WiMax phones as I recall, so I shouldn't buy them according to you since I don't have WiMax where I live.