Totally agreed. A failed startup is definitely worth the time spent. You get to learn about the industry you're attacking, you get to learn about making hard decisions with the a team (and how to pick future partners, which is highly underrated), and you get to learn about all the extra things that it takes to launch a company beyond "come up with idea for thing; make thing". Plus, it's surprising how often things created during the first version of a startup can be reused in a next version.