[pjmlp]

Yes, because we are yet to achieve a mainstream way of doing computing the way he and his peers have envisioned.

Although my IDEs are quite powerful, they are yet far from the Xerox PARC workstations experience used to feel like.

My tablet, even a Surface, aren't as easy to use or programmable in the same way as the Dynabooks were envisioned.

So yes, he is still relevant, because mainstream computing is still catching up to his vision.