Re: Loss of human contact
Interestingly, I worked on a fully remote team for many years, ending just under a decade ago. Never met any of my peers face to face I worked with for a full fifteen years. Most of the teams in the division (several hundred people) were similar, no more than a couple people per roughly ten person team in the same city, and significant percentages of people working full time remote from home.
The key difference was the recognition among the team that the workplace was not our personal life. I had a more active social life then than I've had ever since. I think those that desire more social interaction will find ways to do so.
As to loyalty? I believe that loyalty comes from how you are treated. When I've had a good manager who treated me well, I've felt more loyal. When I was treated as a replaceable machine cog, I didn't feel overly loyal to the company.
I cannot speak conclusively to your statements on productivity, but even the connectivity of twenty years ago is a radically different situation than the 1960s office. I question if those results are still relevant to the physical office today, or if they instead suggest that smaller focused subteams may be more productive today.