Anyone ever wonder why all the Khajiit found on Vvardenfell are Suthay-raht, while only the Ohmes-rhat are found in Highrock and Hamerfell, and in Cyrodiil and Skyrim every Khajiit is a Cathay? What could be the reason (other than character creation technicalities) for this peculiar settling of the cat-like race? Were Elder Scrolls VI to be set in Elsweyr, would we see each of the different types of Khajiit? How about in ESO? Will these different Khajiit be in evidence, and if not, why not?

Your looking for an in-game, lore reason for something that is wholly a tech/dev laziness. BTW: the Devs have said that Morrowind, Oblivion, and Skyrim Khajiit are all Suthay (Leg appearance were tech choice)

ZOS gave a [censored] answer as to why there are only one type of khajiit present in their game:

According to them, Suthay are the most common type of Khajiit and their numbers are greatest.

However this makes no sense what-so-ever. Khajiit are determined by the moon phase they are birthed under, so unless they coordinate coitus, one type wouldnt be more prevalent than another.

Its also important to note that Ohmes Raht were said to be the most common type of Khajiit outside of Elsweyr due to the fact that they are easily accepted into others communities.

With respect, I'd like to see a source indicating they've stated that, otherwise I feel compelled to go with the common thought as others here, that what we've seen over the last few games are different species. (I'm not ignorant to the notion the real reason for the legs was a simple fix to modeling clothes and armor. However, I'd like to believe they put more effort into making a reason that fits to the lore, I'll even accept evolution over 'laziness')

http://www.uesp.net/wiki/Lore_talk:Khajiit

Apart from a few people who appeared in name only like artists and rulers of provinces, there were no Khajiiti NPC's in Daggerfall; the only ohmes-raht in the game was the player character if that. I think the first Pocket Guide to the Empire said that the ohmes were the most commonly seen outside Elsweyr, but since then, it has been suthay-raht.

The inequality in distribution must be because Khajiit only conceive/give birth during certain moon phases depending on factors including where they live, whether by tradition or moon-influenced biology.