Counterpoint: Yesterday's useless robotic dog [0] is... today's useless robotic dog [1]. I've been working on various autonomous robotic technologies long enough with no visible progress that it's starting to feel like vaporware to me.

It's too early to make the prediction with certainty, but I won't be at all surprised if 20 years from now "autonomous delivery drone" is right up there with flying cars and nuclear fusion on the "20 more years" shelf.

[0]: https://en.wikipedia.org/wiki/BigDog

[1]: https://www.bostondynamics.com/spot

Relevant xkcd: https://m.xkcd.com/2128/