Could also be the exact opposite (experienced this with consumer grade electronics based on microcontrollers often enough):

Because of the large capacitors, voltage from the power brick kinda “ramps up” when it is plugged into the wall. The device/its MCU/most specifically its clock circuit however prefers a hard edge of power being turned on, to reliably trigger its power on reset circuit/oscillator.

You can think of it similar to a pendulum/newton’s cradle/metronome - they also prefer one decisive push to get going reliably.

Unplugging the brick for a longer time is still worth a try, but it could also be this.

There’s CookieAutoDelete (or anonymous tabs, containers, …) for the other side of this issue.

How would they ensure this latter thing?

In my current understanding, it’s readily possible today (on Lemmy and related software), what could Meta do to keep this from continuing to work?

I guess this will already have been said, but nonetheless:

I like the feeling of community as it is right now in the Fediverse very much.

Most of me hopes that it will not successfully federate with Meta, ever; or if it “must”, in a way that will be mostly irrelevant to me (communities I wouldn’t subscribe to in the first place, anyway).

I don’t see how that, in turn, would give Meta any control over the parts of the Fediverse that I care about. If they want to join and contribute in good faith, fine. If not, also fine. Why should it change anything for Fediverse “centered” communities?

I never cared about size or majority, but about quality of content and discourse. And I find that in those points, the current Fediverse much outshines anything else I’ve seen (Facebook, Twitter, Reddit, …) in the last decade or so.