I've never paid much attention to model numbers when trying to buy a phone; for feature phones I usually just walk into the carrier-of-choice's shop, filter by

I've never paid much attention to model numbers when trying to buy a phone; for feature phones I usually just walk into the carrier-of-choice's shop, filter by form factor, and then look at which one has the right price point. Most of the time, a lexicographically larger model number means "bigger, better, and more expensive", which is enough of a heuristic if there are only ten models on display. Having lots of models at different price points seems crazy for Apple, but it makes sense for just about anyone else making cell phones. Flooding the market with tons of choices at different price points happens in everything else we buy, from CPUs to cereal boxes to jeans. Plus, if they change a part inside (say, update the CPU, or cut the RAM), the home-tech-support person in me would rather that they change the model number, than sneak in a nontrivial "Rev. 2" update. (This was a big deal with the WRT54G, when people were buying them and flashing custom ROMs that only fit in older models with more memory.)