Most VC funds have an expected lifespan of (roughly) 10 years. Some longer, some shorter.
If your VC makes an investment 2 years into the fund, the expected return must come within 8 years if it's a 10 year fund.
I guess it comes down to what we consider "long term". If "long term" means 5-10 years, then the VC model works.
But if "long term" means 10-25 years or longer, the VC model becomes an unrealistic financing option.