Sorry but this is such a bad take.
Linux is free to install, free to use and most importantly free to learn
What is the alternative? How many people who are now in great jobs would have been unable to teach themselves the skills they need if IIS or another proprietary technology had won the server market instead.
Something had to fill the space, would you rather it was a technology that created barriers for people with the fewest advantages in life?
(Also as others have said, a lot of OSS development is funded by companies. Linux in particular being a great example)
Quanta is just a word (related to quantity) as in: "smallest divisible quantity of"
So in the case of light we would be talking about photons, which are a quanta of light (e.g. discrete "packets" of light).
Light behaves as a wave, e.g. we can talk about the frequency of light. But it's also pretty different from macroscopic waves e.g. it's not accurate to think of them as what your see on a typical sinusoid graph, as at that level things don't really have a fixed shape or position, we're talking more about areas where they "probably" are (see: superposition, HUP etc)
It's useful to think of light in terms of discrete photons for a number of reasons, e.g. in pair production, 1 gamma photon would be sufficient to create 1 electron/positron pair.
Photons also exhibit other particle-like behaviour despite having no rest mass. But the idea of rest mass becomes less significant at that level anyway as the line between energy and mass (e=mc²) gets blurred. And any sufficiently high energy object will likely exhibit some massive properties (hence why we tend to use MeV - a measure of energy - instead of a measure of mass, even when performing calculations with massive particles such as electrons.