Both of these people also did their work in low capital cost areas with fast revision cycles: CS/software and math. Those are areas where individual scale bootstrapping is actually a possibility. There are no garage spaceships, automobile plants, novel surgical procedures (I hope), or nuclear reactors (excepting that wacko who tried to make one from material from hundreds of smoke detectors and turned his yard into a superfund site).
In America you must support yourself and pay for college (unless you go 100% autodidact, which is very hard in its own way). That relegates any additional work to moonlighting, which is very sub-optimal for concentration and is only possible in a few fields anyway. As you get older you may want to start a family, which eliminates most moonlighting time and demands even higher income for support and long term savings.
So the only way to do it in America is to (a) earn a ton of money early and achieve financial independence and then do your innovative work, or (b) take a vow of poverty and celibacy and live like a monk. I guess there's also (c) which is to find a benefactor or find some way to make your work viable as an angel/VC investment, but the former is extremely rare and the latter is only workable in a few fields that have low barriers to entry (like software) and a fairly rapid time from prototype to potential market. For "atoms" rather than "bits" type stuff the initial investment and time horizon are too big for angel/VC and there are very few benefactors/patrons with pockets that deep.
The thing is, when I realized this, these things stopped being cool.
I think there was a lot of hope a long time ago that future technological progress was going to be a lot more open to individuals than it actually is now.
In my guesstimate, there aren't many people alive who have contributed more to humanity's technological progress than Linus.
Not intentionally though. Globalization has led to most of it.
Manufacturing leaving for cheaper climes hollowed out the middle class, made unions impotent, etc.
Hypercompetition has forced companies to be ruthless.
In academia, administrators have taken absolute power for themselves and now enrich themselves at the expense of education and research.
It's quite a mess we've stumbled into.
Globalism was implemented in a market fundamentalist way. No special attention was paid to rights, fairness of trade, etc. because it was assumed that trade and markets and then (magic happens here) and then everything is great and liberal democracy spreads everywhere.
What really happened was corporations and international finance going trans-national and exempting itself from the rule of law and then leveraging foreign totalitarian or lawless regimes to break workers power at the wage negotiating table.
The real long term winners were totalitarians and would be totalitarians though, not the corporations or finance. Capitalists selling nooses and rope, as Marx quipped.
As a society, the boomers made a choice in the late '70s / early '80s: egoism should be rewarded and money is the measure of all things. Everything else was a consequence.
If I had my life to do over I would focus on money and money alone first and defer heavy study into science or engineering or tackling actual hard problems. I did it backwards and so I made everything 10X harder on myself.
Part of the problem is that I was naive and thought the social structures and economic systems that drove this kind of progress in the past (a supportive university system with an academic career path, intelligently allocated science funding, a generally workable middle class economy that you could fall back on) still existed. They don't. We dismantled all that stuff starting in the 1970s because we didn't understand what we had built or why it worked.