Honestly, it's hard to say. Console generations have typically last 7 years lately, so we could likely expect a PS6/Xbox [whatever they decide to call it] around 2027. Which would mean that generation could be planned to last until 2034-ish.
I find it hard to imagine that in 2030 we'd still be gaming much as we have been since the 90s. So there's definitely a part of my brain that assumes huge change will have taken place in the console landscape by then.
That being said, towards the end of the 7th gen everyone many people assumed the 8th gen either would never arrive, would arrive very late, or would be a flop. Instead, the 8th gen was Playstation's second most successful after the 6th gen, and whether you want to count the Wii U or Switch as Nintendo's 8th gen console, it was either their best generation or one of their worst.
So far this generation, consoles have endured a global pandemic delaying many games as well as a chip shortage severely limiting the availability of the hardware. Despite that, the Switch is selling as well as ever, the Series X and S are selling better than the Xbox One was, and the PS5 would be outselling even the high standards set by the PS4 if not for the fact that they are hardly ever available for retail.
One thing these discussions often focus too much on is the internet speeds in North American, Europe and Japan, forgetting that gaming is a huge industry is South America, and the rest of the Asia-Pacific. Many of those places don't have the internet speeds to support high fidelity streaming (heck, Australia is a first-world country and PS Now was never offered due to the middling internet speeds).
If I had to guess, I'd say we will get a 10th gen of consoles, but perhaps they will be focused less on a pure increase in raw power. Perhaps they become more "streaming hub" devices that can also support local storage and rendering, and which integrate the PS/Xbox/Nintendo user interfaces and storefronts. I wouldn't be surprised if they were entirely digital consoles and you had to by an external disc drive, or if the "standard"-priced console was the disc-less one and a "Pro"-type model is launched alongside it with a disc-drive. Perhaps the "standard" model becomes a streaming-only device, and the "Pro" model is the one that supports local storage and rendering?