Missing Features in LCNC for FFF/FDM Printers

I have heard similar stories many times in this forum, but I would like to give a deeper motivation on my defense of USB.

USB is a master-slave protocol, in which the host polls the devices. So no collisions nor congestions are possible.
The latency problem comes because you can never know how much time passes between the event and the communication with the host. Polling period is between 1 ms and 10 ms, which is clearly not human-visible (even though it can still do damages).
Dragging the tool despite repeated user action means that there is a problem in some buffer, that maybe does not consider event priorities (not a USB problem).

WHEN can latency be a problem? Well, only when a device has to say something to the host.
Maybe it needs to update the current position, maybe because a switch has been clicked.
3Dprinters usually have no position feedback, and the switches are for homing only (or slow events, like a filament sensor). While the motion planner is  working, it can take its feedback by itself, since it knows the commanded speed, and the previous position.

I 100% agree that a machine with many stepper drivers will NEVER be able to run on USB, there are plenty of low-latency multiple-devices protocols(EtherCAT, CANBUS, or the recent Time Sensitive Ethernet, just to name a few ), but... we are talking about a 3Dprinter... which will have at most a couple of devices on the bus, and no significant information that needs to travel from device to host.

There are lots of great usb solutions for 3d printers. I don't see LCNC joining the list. Never say never, I guess.

As far as the expense of mesa boards, you might want to look at Remora
forum.linuxcnc.org/18-computer/42276-rem...ller-via-spi?start=0

There pretty much no point in using lcnc when duet and klipper exist.

I could think of some more drawbacks of Duet and Klipper and Marlin, but right now i am fighting the extrusion rate and that is something you can not change while printing, or at all as it requires stopping>slicing>start over>throw the partially printed part
Pretty sure that could be done in LinuxCNC during printing.

That's because the extrusion rate is set in the code generation, just like feed rate in cnc. Both klipper and duet have overrides for extrusion factor overrides and speed overrides.

FWIW, it's kinda nice having LCNC controlling the 3DP and laser cutter and eventually my CNC.  Sorta like: one ring to find them, one ring to bind them, One ring to rule them all.  Unless you like different control systems for all your different machines.  Just a thought.