How much can we afford to forget, if we train machines to remember?

Having machines remember for us has indeed affected human memory for a long time. Socrates complained that the introduction of writing would damage readers' memorization ability: http://neamathisi.com/literacies/chapter-1-literacies-on-a-h...

We used to memorise information, now we memorise search patters and ways to filter and combine sources of information. If anything, it can be exponentially more complex and useful.

It's like the difference between carrying a bag on your own back and managing a transport fleet.