A part of me fantasizes about trying this someday, but the thought of not seeing my friends on a regular basis sounds quite lonely in practice.
Relationships suffer, for sure. I've always been a hardcore loner, and I'm mostly OK with that. I can make friends, and I don't have trouble dating, and I often do when I stay somewhere for more than a couple of months. But, realistically, I'm not good at maintaining relationships, and traveling a lot exacerbates that a lot. Traveling isn't the only factor in this, and it was true even before I started traveling. I'd get into a project or whatever and kinda forget about the rest of the world and the other people in it, sometimes for months at a time. I've been trying to alter this behavior somewhat, as I get older and recognize that real friendships come harder and harder every year.
So..yes. It can be quite lonely in practice. If you don't value alone time very highly, it might be too much. It doesn't have to be lonely, though. Being a traveler is interesting to a lot of people, so if you're at all socially proficient you can make new friends (or romantic partners, if you aren't already satisfied in that area) relatively easily, as long as you do social stuff while traveling (I do social bike rides, tech events, activism, and art/music stuff, when I have social energy to spend). They will probably be fleeting relationships, however. It's pretty rare that I meet someone in my travels that I keep in touch with forever.
Also, as much as I hate facebook and what it's been used for (and is being used for), it is nice to be able to connect up with people that way, since it makes it possible to run into people again later, maybe not even in the same city you met them in. Getting a cell number or email address just means I might contact them if I am back in the city I last saw them in; but with facebook, I might see that someone I know has moved to a city I'm going to, or whatever. It's sort of a live view of who I know, and that's really valuable. Sometimes, those old friends and acquaintances are happy to see me again, and that's nice.
I agree with you. It's pretty lonely 'after a while'. Everything starts to be kind of the same just with a different aesthetic.
People fetishize travel but there's immense joy in the day to day things. Community, family, good food, etc.
My preference is it's better to have a home base with a community and take trips.
My preference would be to take month long trips once or twice a year and come home to a home base.
That being said...I need to travel and get out of my head space and try to do it often.
To be clear this isn't a value judgement, but perhaps a point to consider when thinking about trying this lifestyle.
I enjoy long periods of solitude so it wasn't a big problem for me, but I think most people would probably want to stay in campgrounds and hostels pretty often to get some socialization in.
I picked up hitchhikers a few times, which was usually fun, sometimes smelly, and always interesting.