HogansHero said: "well, "success" is a term of art and so you are trying to change its meaning. I prefer the term you substituted in the 2nd paragraph-"value." I completely agree recoupment is not the sole measure of value.
Regarding investors, my experience is that most are investing in a show because they believe in it (or have been sold on it by someone who does). Yes, there are occasional passion projects, and occasional "should be seen" projects, a few who occasionally invest "for the party" or to gain some access to another investment, but while remaining aware of the risk, most investors seem to be looking forward to the reward."
There are also some investors putting money into the show as part of a long-term plan. One example would be investing in some risky shows to build relationships with lead producers and get the chance to invest in something that has much better prospects. For example, there were very few, if any, first-time investors who were even given the chance to see the offering papers for Hamilton, let alone be able to get any stake in it.