More than 30 years ago. Believe it or not, the Intellivision has the same service, using the same basic technique in 1981:

https://www.intvprime.com/intellivision-faq/intellivision-fa...

https://www.intvfunhouse.com/mattel/playcable.php

(The Atari 2600 got a competitor but despite being the older console it was released in 1983: https://www.wired.com/story/streaming-games-actually-started... )

So, 43 years ago.

Oh, the idea is even older. In 1980, video games downloaded over cable TV, was tested in a few US cities. Intellivision! Same basic idea. Cable service allowed very fast (1 Mbit/s approximately) transmission for the time, so games could transfer in seconds: : https://en.wikipedia.org/wiki/PlayCable

And Sega offered something similar in the USA in the early 1990s too: https://en.wikipedia.org/wiki/Sega_Channel

I think Satellaview in Japan, was the first service of that kind, which was truly successful though.