Now that NEC is exiting the premise-based PBX business, what options will people consider in the coming years? Will you migrate to the newly decoupled Teams voice, Zoom voice, cloud VoIP, or other types of "softswitch solutions?" I assume you could ride the current hardware out for 5-10 years, but risk, cost, and reward will need to be weighed heavily.

At my last company I decided to go Cloud-VOIP (including e-fax), with dedicated POTS lines for the few remaining use cases (elevators, fire systems....), and cell phone repeaters on all floors. It worked well, I would do it again. Current company is also cloud-VOIP but most folks just use their cell phones. 

I remember when we switched from ROLM to NEC. We had a ROLM from the 1950’s and could still find used parts from various places (in 1998). We then replaced the NEC with SKYPE 2015. I’ll bet you will be able to get parts for the NEC for 30-40 years. We struggled to get E-911 to work properly but now there are better options. In general we are satisfied but not quite as reliable as a PBX. So we added red hard line phone in key locations for additional E-911 safety