except the 3GB 1060 is unaffected.No, Ethereum won't be mineable forever. Somewhere late this year or early next year Ethereum will switch to Proof of Stake and you won't be able to mine it with GPU's anymore.
What you linked to is DAG size which is basically memory size requirement.
nor is the 4GB 1050.
nor is the 6GB 1060
Basically NVidia cards are unaffected by DAG size for whatever reason.
When Ethereum moves to POS, we'll have to move onto to other coins - but that date isn't actually set right?
Anyway - my point is -- the difficulty/hash rate isn't increasing for some cards. That's the reason I have four 1080TI mining instead of 8 RX470 I sold off shortly after purchase. Four 1080TI and eight RX470 were relatively equitable value a month ago. I sold the 8 RX470 for $2400 (less eBay/paypal fees). I bought the 4 1080TI for $2800 (ish) -- that and I think 1080TI will hold their value relatively well until Volta comes out (Even if mining dies completely). So there should be minimal value loss on the 1080TI through end of this year, or Q1 next year. If mining busts, then the RX470 cards will sell for like $80 to $100 - instead of $300 -- because the only reason their value is high - IS directly related to mining.