1) I'd be less apprehensive about giving away 8% to any (!) company I found if I knew the network/guidance/community were proven.
2) You need track records of success before the network/guidance/community is seen as worth it. Right now, it's a gamble since you're new.
So you need a population of people willing to take a lower amount of money with a gamble on community quality.
Given that, it seems better off to wait.
if your startup fails, you will never join another as an earlier employer, which is the plan B for most failed founders. becuase now you are a toxic asset to any early stage company which you can be said to be a early founder. now you will only be able to find 9-5 jobs at big Co as your plan B.
It strikes me that the lack of conviction in the people that the Pioneer fund itself is selecting (as evidenced by such a low amount of money for such a high percentage, and lock-in) means that all that they will get is going to be half-baked shower thoughts. Ultimately, you get what you pay for.
And before you object to the notion of exploitation, let's just contrast your quasi-moral claims about loss to "the economy from the loss of ideas and wealth they could have produced," to the rather huge liberties you'll take with the people who you'll be supporting. So are you really concerned about the grand loss to the world of people in whom the world doesn't sufficiently invest, or are you most concerned about maximizing venture capital? These goals are in logical conflict.
We're hoping that becoming a Pioneer vastly increases the odds that you turn your "shower-thought" into something real, even if it takes a few years to mature.
We're going to be making bets on folks substantially before they have the indicia of success that investors screen for. Before anyone could even say "This person will someday found a company." The math for this to be sustainable requires that the equity slice be higher than someone would ask for if they knew 100% of their investments were in high-potential companies.