I guess that depends on how you define console. If you define it as fully closed platform with iterations every 5-7 years, then yes, 8th gen will be the last console gen in that sense. If you define console as a fairly powerful gaming device for you living room, then no, this won't be the last generation of consoles.
From this point forward I fully expect mid-gen upgrades or even fully upgradeable consoles from each of the big 3. PS4K is as close to being confirmed as possible without hearing a confirmation from Sony themselves. An upgradeable Xbox releasing soon is heavily rumored and Phil himself talked about Xbox being upgradeable in the future. Nintendo patented what they call a supplemental computing device, which will likely be used to upgrade NX mid gen.
Don't doubt that Nintendo won't do both. SCD can only do so much. At some point, the hardware becomes a bottleneck. I expect a physical hardware upgrade for the NX and NXDS once every two years each, alternating years of release indefinitely.
Well, this is new.