So do we think now is the right time or are we still too early? Can we build the Star / Lisa today? Side question: isn't it crazy that we still mourn and yearn for technological visions from the 70s? Where's our creativity gone?

It's not crazy, but that doesn't mean it's correct. There is a widespread in many cultures to yearn for a bygone golden age. This isn't to say that things weren't sometimes genuinely better in the past; but people are convinced of this far more often than it is true. As for the 70's, my "don't overthink it" guess would be that the 70's felt more innovative because of the "Wild West" or "low hanging fruit" effect: computing was younger then, less was known and so it was easier to discover new things. Technology, companies, customs, and academic traditions weren't as well established, so there were more opportunities to create your own conventions, establish your own research directions, build systems from the ground up without worrying about compatibility, and so forth. I very much doubt that there's some underlying "loss of creativity". A different explanation would be Bret Victor's claim that the approach to funding science in the 60s & 70s was fundamentally better. I don't remember exactly what he argues, but at least one thing he talks about is a focus on funding people & groups rather than specific project ideas. I'm slightly skeptical of this but haven't looked into it extensively.

We got Open Source. We got the web. Though in various ways undermined, there was good enthusiasm about those developments.

They Promised Us Jetpacks...