Webex/Hangouts/GTM is fine for 90% of the banal, communication meetings. But it really fails for any design meetings that need a whiteboard. I have tried getting my team to use some alternatives, but there is always some eye rolling, and it never sticks around. It doesn't help that the majority of our team is onsite, so any alternative is 100% for my benefit. Also I haven't found an app that can compete with the tactile feeling of a physical board.
Also I feel like I miss out on the "water cooler" talk. Any sort of communication I have is very formal. My team doesn't like using chat casually, so it really hampers my ability to form relationships with them.
Finally, time management is an issue. When you have an office, its much easier to turn on and off. When I am at home too many mornings start late, and too many evenings run long.
It doesn't help that the majority of our team is onsite, so any alternative is 100% for my benefit.
You can even mix on a day-to-day basis, as long as you follow the same schedule. One office had a general practice of everyone in the office Mon-Thur, and then everyone teleworked on Friday. It was great.
The office I'm in now, though, has some people teleworking one day a week, and working four 10s so they're off completely on Friday, and some others working five 8's, in the office every day. It's murder to schedule a time when everyone has access to the same interaction tools.
I do wish that Microsoft would have standardized on thunderbolt 3 as opposed to the surface connector, but between power and all the compatability problems I suppose I get it.
I have a friend I meet for beer on a Thursday every 3 weeks, Family and the Missus occupy the rest, and the sliver of time I have remaining goes to personal dev / gaming.
I don't recall ever caring about being lonesome, so I don't think I got used to it as such.
Everyone is different for sure, but I too would never go back to working in an office!
One thing I did for a while was to rent a little office with two other freelancers a few bicycle minutes away from home. That was the best setup for me. You go out in the morning but still control your work environment.
I've been volunteering with a community theatre this year, which gets me out of the house after work most week days. My mood goes up about 10x when I do this. During the month or so downtime between plays though, things start going bad again.
I'm also involved with some other meetups/clubs and do piano lessons. Putting together a deliberate schedule of "outside activities", at least for me, is absolutely necessary to make it work.
And I would still never go back to working in an office!