Yes, yes. But the Hathi Trust is starting with the opposite assumption: that there is no owner. In fact, if you are not computer savvy and know to look, you cannot protect your rights. The exception to this is having a phone number that is still valid. Otherwise you have to have a known email address (this means known to the Hathi Trust) or find your work on their list and assert your right within the stated time period. Given that the authors are likely to be older than 60 (most recent book I found on the current list published in 1963), it is dependent upon their heirs and assigns to know that this is being done. I have family that has published work and since died, and although it is unlikely that I am entitled to anything, I did not even know about this. They are depending on this lack of knowledge to get away with theft.

Please note that this sort of right could potentially be inherited under a standard "balance of the estate" clause found in most wills.