In most cases, successful inventors of the past didn't have access to capital either. It often took decades of relentless dedication for their ideas to come to life. Sometimes, they even straight up risked their lives (like doctors trying out new therapies on themselves). You could say that's unfair, but it kind of makes sense - this way, only people with a singular focus and huge drive make it to the other end - and it's precisely the kind of people who are most fit to be leading the progress anyway (i.e. it's better for everyone when people who get to do cancer research are obsessed about curing cancer and not just very smart, normal people).
Another advantage of strong individual focus is you can end up owning your own inventions rather than having them assigned away to some extent.
Living off your own technology is not for everyone. Most innovation is not ground-breaking or is so marginal that it actually needs to be highly leveraged to achieve the benefits of scale. Without a large research group to support it is possible to get by on the lesser advances, and if momentum can be built from that it can allow the time and space to gravitate to more potentially impactful approaches compared to modern or established institutional trends.
In many situations it can be a lot easier and less costly & time-consuming to invent another sure-fire energy-saving device for instance, than it would be to risk the resources seeking eminence. You can end up with an unfair advantage at the inventing itself compared to those who divert any effort away from the task, simply because you can not afford to take that kind of risk.
You also have the unfair disadvantage relative to those who basically just toot their own horn, but everybody has that.
