It really is clear as to why this team haven't updated the R1 as if they did there is no real reason to buy the XR500 at all.
I have not got an R1 but why would I buy an R1? You post makes no sense. R1 owners who are happy with the unit would want the update, new buyers would not buy the R1 probably based on hardware alone. After all who in 2018 is going to buy a router with a 600Mhz CPU and 128MB of ram, that has b/g/n only when 802.11ac is the norm now. The Netgear R7000 was released in 2014 with a 1Ghz Dual core CPU and 256MB ram and 128MB flash and 3x3:3 MIMO along with 802.11ac. Those specs are what people are looking for and the R7000 is still going strong even now, and able to to push 4K HDR/Dolby vision around around their homes wirelessly let alone the myriad of other devices that they own which also now need faster CPU's and greater bandwidth at faster speeds. Also it wont be long before 802.11ax is hitting the shelves, also WPA3 is coming and the new routers should get this with a firmware update it now seems, I wonder if the the R1 is capable of that upgrade? Yes I know Ethernet is still the best way to hook things up, but my 4K OLED AF8 can watch Netflix in 4K HDR over wifi with no buffering and I can still browse on my iPad or take a facetime call etc. I think the R1 would really struggle.
I highly doubt they are trying to push the XR500, because if people look at the hardware specs for a modern LAN the R1 makes no sense. I would imagine if the R1 was made by a Asus/TP-Link/Netgear etc would it be EOL by now, as its not really powerful enough. Gamers also do a whole bunch of other stuff and using the R1 then buying an expensive router to put into AP mode does not make financial sense to many people these days. This is why I think the Netgear conspiracy is flawed. You can all go round in circles forever trying to guess about the last minute pull of DumaOS and I would agree the timing was not great in all honesty, but I think its just about hardware really nothing more. The R1 was released in 2014/2015 depending on country with under powered specs even then, the R7000 was also released at the same time with much better specs (1Ghz Dual core CPU and 256MB ram and 128MB flash and 3x3:3 MIMO along with 802.11ac) as I wrote above. So the R1 was tired at launch really, but the software made it so very special.
At the end of the day the R1 is getting old and underpowered, so new buyers would not buy the R1. I imagine, if the XR500 did not exist an Asus AC5300 or Netgear R7800 would do for most as it handles other network needs easily as well as gaming for the majority. Looking on Amazon UK right now the R1 is not even available anymore and they are not sure when they will get stock again. It may be as simple as its just does not have the grunt or the Wi-Fi specs people would be looking for now.
So your argument "I can say It really is clear as to why this team haven't updated the R1 as if they did there is no real reason to buy the XR500 at all" I think is flawed, because the majority of new users including myself would not buy a 600Mhz 128mb ram b/g/n router no matter what software was on it in 2018. That's just my take.