And,
again, what's your point? Why this isn't an automatic update -
why does Google not put the effort of upgrading their old systems while Microsoft just do it? Apart from the ill-fated Surface RT, Microsoft's old devices still receive periodic updates with minimal intervention. Why Google can't do the same thing?
Edit: actually, Microsoft is even kind enough to support clusterf***s that are not even their fault - https://arstechnica.com/gadgets/2017/07/clover-trail-systems.... As another comment pointed out, just give security updates if it's too onerous to upgrade to the next OS - which in CN60 is demonstrated to be a pure business decision.