Sorry I just don't believe that. Manufacturers make bigger phones because they can charge more for them. Most people I speak to (techy and non-techy) all want smaller phones.People don't generally buy smaller phones unfortunately, otherwise there would still be an iPhone 5 sized device or Sony Compact devices. The manufacturers already have this data and it's not worth their while to produce them.
It's like the headphone jack debacle; part "trend" thanks to Apple, partly because it helps the manufacturer reduce their cost.