There is actually a very good and valid reason to. If you live in an area that already has WiMax, then you will have a 4G phone with a functioning 4G network, whereas if you live in a WiMax area and you get an LTE phone you need to wait up to two years to get LTE in your area. That being said, that isn't that many areas/people that actually have a reason to buy a wimax phone.
Actually a horrible analogy. The DVD was released in 95. It wasn't until years later that they caught on since at the time you still needed a VCR if you wanted to record a show you were going to miss. TiVo came out around 99 and weren't out DVD-Rs until 05 (according to wikipedia). Many people at this time didn't buy DVD players because they were much more expensive and there wasn't much coming out in DVD (same as there isn't much in the way of 3D movies being released right now)*. The much better analogy would be buying an HD-DVD player after Blu-Ray one the HD war.
*I've still heard reasons why VHS is better then DVD recently such as a minor scratch can make a DVD useless while minor damage to the tape makes only a second or so. And I've found people who claim the video quality is better (sort of like some people prefer the sound of vinyl to cd). But all of these things I have heard other people claim and never noticed myself (well other then the damage bit)