- Hub is good in theory, maybe in the early phase of modern or exploration for some good influence boost, and for those small settlements used to fill gaps in your territory. However, something about them is severely nerfed. I'm sure there's some cheese that would ruin the game if they buffed hub towns, but frankly I think they should because I think no one's really using them.
In my first GOTM I specialised my second settlement that was settled as a small town just to claim 3 resources into a hub town, as I noticed that it had 4 connections, that resulted in 8 influence per turn. Over 100 turns it will bring me 800 influence that is good for like 4-5 spy-stolen techs/civics if I remember the Explo stealing cost and maintenance correctly. So just this town alone lets me concentrate on my chosen branches of the tech and civics tree and not fall too far behind on the other branches. As you can only run one spy operation for tech and one for civic at the same time, this one town will basically cover my spying needs for the entire Age, leaving other influence from buildings for endeavors interaction with AI civs and IP taming.
- Hub towns are sometimes marginally useful in modern for filling gaps and generating a little early influence but otherwise ignore them.
Given the above, I think that they do not deserve to be ignored. A couple of well connected small hub towns can bring quite an amount of influence. And the best part is that they can be put to work rather quickly, as you can drop them in the middle of your future cities, to claim just a few resources, and be specialized as soon as they reach pop 7, which can be helped by rural displacement or a lucky migrant event. The earlier the town starts working the better.
Which leads me to doubt this assumption as well:
- In Antiquity, build all towns as if they're going to become cities. Look for resource adjacencies.
I'd say, plan your settling already with a vision of what you're settling - a town with a targeted specialization, or a city. Because a town does not need all that city sized space, it only needs to claim the resources and/or fertile/food rich tiles, and time spent growing is time when the town is not contributing to the greater good. Cities will mostly need all the 3 rings reserved for them for all the buildings and wonders, so leave more space for them than for the towns.
The purpose of towns, as I understand it, is to help overfilling cities with food, so that they can have all those specialists. You can have 20-30 cities with no towns, of course, but probably they will not grow into mega-cities. But if you have 7 cities helped by 20 towns or so, those cities will be huge, with lots of specialists, and as for production, frankly, who needs all that numerous production opportunities when you can just buy most things with gold?