Google has officially announced the discontinuation of the Home Max, and Home Mini.
Current Google Home Max users have nothing to worry about. Google is not discontinuing the service to currently installed devices.
QUOTE: We’ll continue to offer software updates and security fixes to Google Home Max devices. We’re committed to delivering great sound and whole home audio features across all of our Assistant-enabled products. CITATION: Google
Should I Buy a Google Home Max in 2020?
Seeing as Google is not going to stop supporting the device, then sure, you could. But Google is replacing the Google Home devices with the Nest Audio. They are only $99, so it’s much cheaper than the older Google Home option.