I'd really be interested in seeing the blueprint for how to bootstrap a successful synthbio startup starting with a single, garage-sized DNA foundry.
The large rounds are due to 1) amazing exit environment attracting tons of capital and 2) no growth in number of funded startups in the last decade. More money chasing fewer deals = larger $ per deal
From what I see professors don't typically don't join companies, but rather stay in academia and advise re the science. The management team is generally comprised of a team of serial entrepreneurs or 20-30 year big pharma veterans. Most startups are seeded in house by a cadre of biotech VCs
Will write a post about the blueprint for these startups, but in broad strokes it's 1) $1-5M seed round to make sure the academic work is reproducible, generate IP and derisk core hypotheses with a few "killer experiments". If that looks good, there will be a $20-50M (or even $100M+) series a that is typically designed to get through human proof of concept in phase 1. This is when the exit window opens, and the exit window these days is big. Should be noted that most of these rounds are tranched
There are several Bruce booth blog posts that walk through this in more detail. Bruce is a partner at atlas venture, a leading early stage biotech fund, and he's one of the few biotech VCs who blogs. Don't have specific links offhand but can find a few if interested
It's tough to bootstrap in biopharma because you don't generate revenue basically ever. You could theoretically sell assays or reagents or something to get revenue to support the real r&d but it's often preferable to get VC money. The best exits require $10-20M minimum