The right private investor/angel is also a good route. This should essentially be someone who wants to join you in the business, not someone who is looking for a specific return timeline on their investment. That's a big differentiator between a good angel and a VC.
Traditionally, you start the business after you have some experience in the field, and either have some skill you can use to drive some revenue, or some capital.
This idea that you start a product business (rather than a business selling your labor directly) right out of school seems like a new one.
It's not so much 'let' as "pay them lots of money to"
as for the encumbrances, well, we all make choices. Children don't magically appear when you hit 30. Personally, I find it really surprising that people who choose to have children seem to be able to compete with the childfree in top jobs... but it seems they can, so what do I know?
I think you make a great point, but out of curiosity, what do you suggest are the best avenues for funding a tech business in the more traditional revenue-driven-growth model, if you're not bringing enough seed capital to get off the ground on your own? It seems like what's missing is an accessible happy medium.