your hunch is correct. as engineers we're attached to .io ourselves, but outside the developer community .io invites confusion -- as we grow, .com is simpler.
Outside of the tech field everything but a .com is viewed negatively.
When I worked for clients they used to really push hard for a .com. They'd rather have a 25 character .com than use anything else. My guess is that they only trust .com.
Photographers are also open to alternative domains. Our company had to change its name early in its existence. When we were explaining it to some photographers we work with, they were surprised that we didn't go with .co or .photography (shudder).
.com is simple and guaranteed to work. By that I mean both with humans (who just assume '.com' is the thing that goes in the location bar) and with computers (Interac e-transfers, a way of moving money in Canada by sending to an email address, don't work with .photography domains).
Well, dot net has a historical connotation to being used by companies that shared a name with a larger, more reputable company and dot org is for charities. Dot com is simply what people are most likely to remember. This doesn't matter so much if all you're doing is running a mobile app, but when you've got a site to worry about, the domain extension matters.
regardless, it will sound outdated in a few years. its not based on what is currently fashionable.
its not a name you should give your company if you want to last say 10 or 50 years
in germany there are all these companies called 24 like http://www.immobilienscout24.de/ because back in the 90s this was the trendy german website thing. now it just sounds silly
Someone recently asked me what country our company that had an .io domain was located in. Explaining that it was shorthand for input/output and that it was a tech thing was lost on them.
Does the tld really matter? My hunch is that .io is perceived as a toy product TLD and .com is where 'real' business is done?
This kind of sentiment sucks though because other startups probably see it as well and will needlessly shell out cash for a .com.