Loneliness only sets in when you have nothing else to do and you’re all alone. If you’re swinging a hammer at a hot forge for 16 hours a day loneliness is a secondary concern.
[1] https://groups.csail.mit.edu/mac/users/rauch/worktime/hours_...
This is the opposite of loneliness.
Recently society has been pushing for these two things, at the expense of personal connections. That means many successful people are working jobs that are out of the experience of their parents. They also do not necessarily share a lot of experiences of their formative years with the people they work with. All of this comes from personal freedom, but at the expense of being close to the people you spend your time with. I suppose you could also put it that its at the expense of spending time with the people you are close to.
Maybe, our current obsession as a society with personal freedom and social mobility is an extreme which is itself the cause of all the loneliness. It's an extreme which reduces the stability and cohesion of our society, because in promoting the freedom of the individual above all else, you've harmed the social connections which make a society work.
Maybe there's a happy medium, but I think we might have passed it by over a century back.
How is this different than what the majority of civilization had to do throughout history? People have always clung to their profession as their identity. Hell, people used to name themselves after their profession.
If that is the problem, then push for fewer hours worked per week.