This is extremely situational. When I was in a larger house and had no kids, WFH was an easy way to avoid interruptions.
Moving to a smaller house (more expensive city) and having kids flipped the situation around. Avoiding interruptions at home was extremely difficult because I was always only a door away from someone asking a “quick favor”.
It’s not just me: As a remote manger I can almost always tell when summer break starts for everyone’s area because there’s a stepwise decline in productive when people’s kids aren’t in school.
Likewise, the office environment makes all the difference. I’ve worked in open-office spaces where everybody respected each other and concentration was the default. I’ve also worked in private-office spaces where I could expect knocks on my door every 15 minutes or less because the culture was so bad that interrupting the engineers was the default practice.
Lately, I’ve felt that fully remote has been the worst of all worlds. Once Slack becomes the default I’m pinged from every angle all day long. It’s hard to push back against people who want answers now now now and know they can get your attention by typing the right few characters into Slack. Comes down to culture, but Slack makes it easy for people to quietly interrupt people directly whereas it was much easier to police the interruptions (as a manager) when I could literally see the offenders bothering the engineers.