When I read posts like this - however well-intentioned - I just see a person without kids or other responsibilities, who thinks it would be 'fun' to fly out to some town and hang with their colleagues 24/7 for those seven days, and forgetting that for a lot of people this would be difficult or impossible. At home there can be children that need to be looked after, or an elderly parent who needs a visit, or a partner who works nights or a disability that would make this type of 'cool' get-together impossible or extremely stressful.
On the team, "people without children" are the minority. We do have member s on the team with disabled elders, elders requiring care, disabled children. Lifestock even. We do have people with all manner of volunteer responsibilities too.
We have discussed this extensively internally. To all of these people, it is massively easier to clear up 1 full week with 3-4 months of lead time, than to free up 2-3 days per week permanently. That's why whe chose this mode.
I don't think it's nearly as 'tech startup burnout' culture as you're envisioning here, people travel for work functions regularly in other sectors of work. Nearly all my aforementioned coworkers on my team had children and lives that they were able to allow their temporary separation from. I dont think it's anyone else's responsibility to fix but your own if making accommodations and planning to meet other people makes you stressed.
Just yell at people to be in the office for 2 days per week for no reason? Meh. Why?
Organize a week to have all local and international employees together for a week once or twice a year, schedule big organizational meetings and important discussions in that week, sponsor dinner and lunch together, have a team event or three? Just accept that concrete and hard productivity will crash for that week, and consider it a social event? That's actually nice and valuable.