Well, a loan would have set terms and schedules of repayment and default.
For investors, the 3x & 20% figures I gave are not formalized terms of payback. Instead, they are desirable financial targets for the investor so they can be considered a prestigious firm that attracts capital from more limited partners. Slack won't be in "default" if they provide 0% return to Softbank. However, future limited partners like university endowments or police/firemen pensions will avoid underperforming VCs that deliver low or negative returns. (If VCs don't perform to expecations, the market will punish them and they will shut down.[1])
To trace the causal chain, VCs want 20%+ because your grandmother and her pension plan investing in the VCs want 20%.
For investors, the 3x & 20% figures I gave are not formalized terms of payback. Instead, they are desirable financial targets for the investor so they can be considered a prestigious firm that attracts capital from more limited partners. Slack won't be in "default" if they provide 0% return to Softbank. However, future limited partners like university endowments or police/firemen pensions will avoid underperforming VCs that deliver low or negative returns. (If VCs don't perform to expecations, the market will punish them and they will shut down.[1])
To trace the causal chain, VCs want 20%+ because your grandmother and her pension plan investing in the VCs want 20%.
[1] http://www.businessinsider.com/death-of-venture-capital-2011...