App compatability. Tried several micro android phones and it was tough to switch because a lot of apps don't support lower/smaller resolutions or even the older customized android versions these phones ship with
Phones got bigger, but now we have smart watches with cellular (i.e. wrist phones), so we have even smaller phones than before.
I prefer my old iPhone 8 to the new models, but without the updates it's no longer useful. I was waiting for 4th Gen SE but it never came, but in practice it's the same width and less than 2 centimetres taller. If I could have a shorter phone (like an iPhone 8 without the bezel) that would be amazing.
I tried small Androids in the past, had a Sony Xperia compact (Z1?) and loved it until it very literally fell apart.
Rakuten still makes nice small androids and you can import them pretty easy from Japan.
I have a Doro and it’s great.
Happy owner of an iPhone SE here. I feel like the large manufacturers have trouble selling small phones because they just don't understand the small phone market. It's a lot like the electric vehicle market before Tesla came along. When the Prius was the best electric car on the market, car executives thought that electric cars were for hippies who wanted to make an environmental statement and who didn't care about horsepower or style. Then Tesla came along and ate their lunch because they understood the market better.
The offerings on the market, including the SE (which is probably the best small phone), seem to say, based upon features and price point, "Here is a phone for those of you who can't afford a full-size phone". But that's not why we want a small phone. I would have happily paid twice the price for my SE, so for me the low price was a bonus, but it's not a bonus when they are pricing them too low for sustainability. They should jack up the price and get more margin from it. We'd still buy it.
The number one reason why I prefer a small phone, is because I have plenty of other computers. Your 'big' phone screen doesn't impress my gaming PC. So what I want is a device that fits a niche in my ecosystem of devices, and that niche is portability. Anything that takes away from that is a minus because it's trying to do the job of some other device, which I already own. In other words, make a small phone for professionals. There are plenty of us, we like to buy devices, and we have money. Features we would be willing to pay for include working with our other devices and not having bugs associated with software expecting bigger screens.
For people whose only computer is their phone, big screens totally make sense. And I understand that is the majority of people. But there are millions of people who have another computer other than their phone. The manufacturers are discontinuing the dirt bike because they'd rather sell you an Escalade, but there is an unaddressed market out there for a Ducati.