In the EOL notice Intel did say that someone else would continue to manufacture the Arduino 101 but I was also confused as to how that was possible if they weren't making Curie modules anymore. There was actually a long stretch of the 101 not being available in the Arduino store but now it's available for both store locales and Arduino has been promoting their CTC 101 educational program, which uses the Arduino 101.
I suspect the people laid off were the Intel employees and any further development work will be done by Arduino employees or volunteers. It does seem like development work has not been active recently. In this post:
Massimo Banzi said there would be a new release of the core in August 2017. Sure enough, the 2.2.0 release was made Aug 18, 2017. However, that was tagged as a "pre-release" and was never made available via Boards Manager so probably very few people are actually using it.
I was happy to find that a simple, non-controversial pull request I submitted to the repository was quickly merged and an issue report I filed was quickly resolved so there definitely is still some life in the project.
The 101 was sold out for a long time following the notice from Intel but then it did come back in stock for a while, now it's out of stock again. I don't think we can draw any conclusions from that since it's quite common for Arduino products to be sold out in the Arduino store. Arduino has still been promoting their CTC 101 kits that use the Arduino 101 board but I noticed their latest educational product, the Arduino Engineering Kit, uses the MKR1000 instead.