I don't know, but I feel like we already have the "telepathic grandfather interface." Or at least we try to have it. My iPhone is constantly guessing at things to suggest to me (I use the share button a lot in different apps) and it's wrong more often than not, forcing me to constantly hunt for things (to say nothing about autocorrect, which is constantly changing correct words that I'd previously typed into incorrect ones)! It doesn't even use a basic, sensible LRU eviction policy. It has some totally inscrutable method of determining what to suggest!
If we want an interface that actually lets us work near the speed of thought, it can't be anything that re-arranges options behind our back all the time. Imagine if you went into your kitchen to cook something and the contents of all your drawers and cupboards had been re-arranged without your knowledge! It would be a total nightmare!
We already knew decades ago that spatial interfaces [1] are superior to everything else when it comes to working quickly. You can walk into a familiar room and instinctively turn on a light by reaching for the switch without even looking. With a well-organized kitchen an experienced chef (or even a skilled home cook) can cook a very complicated dish very efficiently when they know where all of the utensils are so that they don't need to go hunting for everything.
Yet today it seems like all software is constantly trying to guess what we want and in the process ends up rearranging everything so that we never feel comfortable using our computers anymore. I REALLY miss using Mac OS 9 (and earlier). At some point I need to set up some vintage Macs to use it again, though its usefulness at browsing the web is rather limited these days (mostly due to protocol changes, but also due to JavaScript). It'd be really nice to have a modern browser running on a vintage Mac, though the limited RAM would be a serious problem.
[1] https://arstechnica.com/gadgets/2003/04/finder/