My 2 cents
NXP promises a 10 year longevity for select micros.
The LPC1778FET180 used on the G120 is part of the program with a longevity date of
That should give 8 more years, after which there may (or not) be a pin compatible replacement with a different core.
The chip will be around for that time and there will an EOL notification from NXP, with a last time buy etc. etc.
So say these chips can be sourced 8 to 10 more years, GHI should be able to make the modules through the standard catalog / special order or turnkey for the same duration. Firmware development may or may not continue for the same duration, but you can always use the frozen mature firmware to implement the same features as of today. Please make sure to archive the firmware and corresponding visual studio versions.
… this is my thoughts and I am sure GHI would be able to provide the authoritative answer.