I suspect that (1) you don't have strong relationships with the people that you've only communicated with via voice, (2) if you do, then it took a very long (multi-year) time to create that trust: significantly longer than through face-to-face communication, (3) you do not do a active, engaging brainstorming and problem solving sessions (e.g. whiteboarding) with your colleagues that you communicate with voice only.

I see some sort of assumption in your comment that I should be bonding with people I work with -- and by "bonding" I mean stepping outside the of work relationships. I don't aim for that. If it happens naturally, I welcome it. But I don't actively pursue it.

But your assumptions are mostly false: I've actively brainstormed and planned with people in voice-only sessions -- and they rarely exceeded 25-30 minutes. And that went on and on for the 1-year contract, every week or two, and only once did we have trouble getting a message across.

Building trust can take anywhere from 2 to 8 weeks if you are a down-to-earth productive programmer -- which I am. Not sure where your multi-year idea of building trust comes from?

I am not attacking you. But I can't stand behind this very widely believed legend that face-to-face trumps everything. That's provably false in literally half my work relationships during my 17-year-long career.

When people have common vision and are working honestly for the interests of their employer -- and are professionals -- things go pretty smoothly and the machine gets oiled fast.