I don't feel like you read my post at all or are replying to anything I've said. You're repeating the same assertions without moving the argument along or talking details. Rather than recognize some similarity, rather than taking any kind of parallax view, rather than making friends, I feel like you've adopted a combatative and quite limited stance, and I think it's a shame you're not willing to chalk up some wins where a monolithic kernel has loosened up & allowed some new microkernel or microkernel-ish either offloading or sharing of responsibilities.

I provided two pretty amazing examples already of how really amazing new userland capabilities were made by having a configurable kernel. You keep ignoring that eBPF may be code running in the kernel, but it also enables not running a dump-truck load of kernel modules that a user would need, while being more flexible, while letting a non-privileged isolated process either have control (ring -1) as the networking Calico/Cilium example shows off, or even more radically by moving the entire task into userland (ExtFUSE) by using eBPF as an io-port with the kernel to let the external process do more of the tasks than it could have before.

You seem to be very rooted in a very precise & narrow minded view of what's afoot here. And fixated on any kernel code being disqualifying, even though it keeps being examples of less & less kernel code running. I think I've really given you a ton of great evidence already, & tried to help you break free of such a narrow conception. My examples really show how eBPF has helped move a ton of work from kernel into userland. I don't think it should be so hard to communicate this, but I'll say it yet again:

programmable kernels sometimes will be programmed to do less in the kernel. That's what we've seen.

(But they can also be used to add more to the kernel too. To repeat again: eBPF is not inherently MK nor inherently monolithic; it depends on what it's used for!)

You talk about Fuse's downside, again boosterizing microkernels, but again, it's like you haven't read my post: where I mention how eBPF was used to greatly speed up & to add brand new novel capabilities neither kernel nor FUSE could do before enhance & Extend FUSE. That's what I keep trying to emphasize. If you have a fixed all-encompassing monolithic kernel, the boundaries are fixed. By introducing eBPF programmability, there's far more flexibility to calve off tasks, to pull them out of the kernel. eBPF is sometimes just a communication tool, not a processing tool, to get the data for the task out of the kernel, into userland, and that 110% qualifies as a microkernel-y thing.

Again, to your points, I said I'd be less interested in trying to claim the Cilium/Calico model is microkernel-ish, because as you say, the data-plane remains in the kernel (although I think it's not hard to recognize that even though it's a different architectural pattern than MK it's still a revolution in moving huge responsibiliites out of the kernel & into userland, & getting the lions share of MK benefits). But the ExtFUSE model shows that that's not the only thing one can do with eBPF (allow a "policy agent", which still seems like a colossal MK-ish win to me!), it shows how it can also help to move work itself outside the kernel in new novel ways.

Rather than focusing on eBPF being something "in the kernel", I think everyone needs to step back & re-ask themselves what eBPF is. It's a malleability system. It's a way to make the kernel programmable. As I've said again and again, that isn't inherently microkernely. But in a huge number of examples, users do exactly that: take things that the kernel would be doing and they make a small eBPF shim to replace complex kernel code with a small port, that sends the task out to userland, where userland does the work. This is quite obviously microkernely.