You can't get to very high chamber pressures with those, and then maybe aerospike was a way to work around the limitations.
Then XLR-129 and SSME came along with staged combustion cycle and you can just have higher pressure engines. They can both run at sea level and still have a decent efficiency in vacuum.
The linear aerospike for X-33 was kind of a neat tech demo and fit in with the whole shape of the vehicle and composites, non-tubular tanks and large base area. Maybe too many new things at once in retrospect.
Tomatoes are disgusting.
He said near the end of the video 2 years ago, "I'm not sure if I got a rotating detonation wave": https://www.youtube.com/watch?v=fRMMSyCcTDI