I don't think we know the real verdict of Steve's manual transmission. I don't think 300,000 miles on a manual transmission is a lot. I can see replacing the clutch, but I am not going to boast about the reliability of these cars if the manual transmissions go before the first clutch is replaced.
A delivery guy using a 2007 RWD Nissan Frontier replaced his first clutch at 801,000 miles. His truck has gone over 1 million miles & there's no mention of having transmission issues.
https://www.youtube.com/watch?v=lAi9o8SXjNg&t=136s
He was near 1,000,000 miles when this clip was made. He has reached over 1,000,000 miles now, & Nissan gave him a new truck for free.
I wouldn't expect a manual transmission to go out before the first clutch or even the engine for that matter. If his car is done at 300,000 miles because of the transmission, I am disappointed. If it's a simple transmission fix, that's different. I wouldn't boast about a manual transmission making 300,000 miles before needing to be replaced. I wouldn't slam it either, however.