It would be helpful to run out the math on the $500K investment: what's the post-money on that investment when it was made? How much capital did this mythical sold-for-$10M in 5-or-6 years company raise? (Or did it survive for a half decade on a total investment of $500K?) What was the headcount and the revenue and the burn? (And to whom does it sell for $10M?) Assuming that it wasn't a wipeout, you'll quickly find that the math doesn't... math: if you have somehow conjured a successful outcome in your mind, what you likely have is not a venture-scale business.

That’s not necessarily venture returns so LPs might not be interested. Selling secondaries is also a pain as you generally have to pay fees and sell at a discount.