Assuming you've decided to take VC, good ones won't invest small amounts of money. And this is separate from valuation; this applies even at the A stage. The reason is they want 18%+ ownership, ideally 22%. If they get less ownership, even if they have a big enough fund to fully exercise their pro-rata rights, they don't get a big enough return in a success. Hence someone who would be willing to put in $4m for 20% will be unwilling to put in $1m for 5%, or even $500k for 5%. The upside just isn't there.

A simpler explanation is that it's all driven by fund size. We all have the same 24 hours/day, 7 days/week and all investments require analysis and oversight. If I'm a VC with 600-800 million to deploy (typical large fund size), I can do, 30-40 deals/year, maybe, only if the diligence checks out, a partner is willing to commit 5-7 years to being on their board, and various other things work out.

That narrows you right away down to $20-30 million checks, maybe less if you keep reserves around for pro rata rights, but still, nobody's getting $500K out of this fund. Ownership is whatever it needs to be to generate the right returns for the fund. Also keep in mind, syndication is very common in VC so one $20 million check might be part of an overall round size of $50 million or more. Don't even bother with that if you can't show line of sight to nine, or ideally ten figures, of enterprise value.