It's important in the historical context of the Alpha AXP to also remember the DEC PRISM architecture. Canceled in 1988. One of many architectures killed off by DEC.
Jupiter was just a PDP-10, I don't think killing Jupiter was bad. The VAX was insanely successful and adopted by a large amount of people. And Jupiter was a very expensive project and it basically failed to do what it wanted to do and was already late. They stopped with PDP-10 because nobody seemed to be able to make a next generation architecture work.
Arguably, all ECL projects should have been killed, even Venus.
https://en.wikipedia.org/wiki/DEC_PRISM
Killing Prism sent David Cutler into the arms of Microsoft.
Another dead architecture was Jupiter: https://en.wikipedia.org/wiki/Jupiter_project
Killing Jupiter sent many of DEC's DECsystem-10 customers to IBM.
Years later, they both seem like bad decisions.