If I have a standup at 10am every day, this guarantees that I'm not going to ever get anything substantial done before 10am. A 3pm weekly meeting can mostly destroy my ability to get in to deep work for that afternoon.
I don't "schedule" deep work, it is a thing that happens as a combination of what needs to be done, the time available, minor tasks, and interruptions.
Daily and weekly meetings significantly reduce the surface area available for these things to happen, and often serve as a source of boredom and frustration, being in a room with people who obviously don't have anything to say, saying words because they're supposed to.
The whole point of 1on1s and retrospectives is to optimize your work. If you literally only have these two meetings per week and you still find that unreasonably disruptive, then you could discuss dropping them to once a fortnight. If you still find those two meetings per fortnight unreasonably disruptive, and you really get absolutely zero benefit from them whatsoever, perhaps you should be working as an independent contractor and not a salaried employeee with a team of colleagues and a manager.
I do understand where you're coming from. I have had several direct reports who never had anything at all to say in their 1on1s, who had no interest in setting goals, no interest in advancing in the company, no interest in improving their workflow, who honestly just wanted to sit down, do the work, get paid, go home. That's fine, and it's useful to have some people on the team who want to work that way, but they really are a minority of people I have worked with in "normal" company environments. To be frank, I would prefer to work that way myself, but that's not really how most companies operate, because most companies are geared for growth, so it's not enough to just stay at the same level of productivity forever. The goal for most companies is to continuously improve and increase their output, forever. This is why most companies see value in having these meetings, because they are a way to focus employees on becoming ever more productive.
That escalated quickly.
Good points, though you're talking past each other a bit. (I'm not disagreeing about 121s' value nor flow's unschedulability.)
You should try it!
I do know how easy it is to get in the zone as a developer, and subsequently feel frustrated that a useless meeting just popped up in the middle of your flow, but that's not a good reason to write off 1on1s entirely. Worst case your flow will be interrupted once a week. Two if your team has a weekly retrospective as well. If two interruptions per week is significantly damaging your productivity, something is wrong.
Personally, I am not a fan of meetings in general, and I do consider many of them to be useless. But 1on1s and retrospectives are the two that I mandate in the teams that I lead - one is for the health of my reports, and the other is for the health of the team. All other meetings can and should be optional. If someone is feeling snowed under by all the other meetings, then it's exactly during the 1on1 or retro when those feelings can be shared. If you don't have those meetings, then you're relying on everyone on the team to always speak up whenever they need help, and while that might work for certain, very assertive and/or self-centered employees, it doesn't work for everyone. For that reason I think it's important to schedule these times in deliberately to give people the opportunity to express themselves.
When there isn't a culture of open communication - which is established through regular meetings of this sort - many employees find it difficult to be honest about their challenges and difficulties (on the negative side) or goals and aspirations (on the positive side). In either case I believe it improves productivity and retention to give employees dedicated space to talk about that stuff.