The situation

Particle is an IoT company specializing in a combination of hardware and cloud services. The great benefit of Particle is that you get a streamlined over-the-air update/programming setup, online management, and a lot of convenience features around exposing functions and variables to your own web requests.

With a customer update and forum post, Particle just announced the end of support for their two year old mesh technology. Built on top of the Nordic nRF52840 and OpenThread, the technology allowed for gateway devices (named Argon and Boron, Wi-Fi and Cellular) to provide a connection to the outside world while node devices (Xenon) would connect to each other and, when needing an internet connection, call out through the gateway.

The announcement makes clear that the xenon line will no longer be supported and the gateway devices will function as connected, but standalone, boards.

The announcement.

My take

Any company with multiple products faces this situation eventually: what do you do when one or more of your products is no longer profitable, whether it is not generating enough revenue or costs to build/design/support are too high? If you end the product line, you have to determine the risk of doing so.
For products such as Windows, a published support plan mitigates risk for customers. If I were to install Windows 8 today, I can easily look at the Microsoft support plan and see when it will no longer be supported. I cannot claim I was not informed.
For any product that wants to be used by commercial entities, you need predictability, reliability, and unambiguous support. Google is notorious for undermining these factors in all but its core product suite. Google Stadia? We promise we're really keen on games. Trust us! Google Inbox? Sorry, but we got bored (I'm sure it's not the reason, but I'm bitter about that one).
It's not a good look. Google gets away with it because it can rely on the fact that it's the biggest player in most markets.

Which brings us back to Particle.
In my opinion, the death of mesh and the Xenon is the signal to any sensible potential or current customer of Particle that you should not trust them with your revenue. Particle likes to tout the use of its boards in industry; what happens to anyone using the Xenon line in a product? You have a year to find an alternative. In Product timelines, that's gun-to-the-head territory.

Particle recommends using either CircuitPython or the OpenThreads SDK as an alternative, but neither of those options allow the Xenon to connect to a gateway. Without a gateway, there's no access to Particle Cloud. Without the Particle Cloud...well, why am I dealing with Particle at all?
None of this means Particle will end any of their other products, but the problem I see is that you can't guarantee that.

In one move, in my opinion, Particle just signaled that it is for hobbyists and proof-of-concepts only. If you need a real-world solution, roll your own. It will take more time, it will cost more money up-front, but it's yours. If you rely on anyone else, you trade convenience for uncertainty. If you take that bet, you have a better tolerance for risk than me.