Well, if you're a inventor, you look at the prior art to see if it's been done before. I hold six issued patents, two of which were very profitable. I had one patent rejected because I missed relevant prior art from 1948.
That said, this project isn’t well summarized as merely “tiny projectors”. Many patents have been granted for systems that include parts that are also patented. Indeed, I can see recently granted patents that include digital projectors. And many products have good sales without being patented; patents are not the end-all of invention. So I feel like you’ve been much too quick to dismiss.
Who iterate and hone until they have something worth existing in today’s world—often doing do more publicly than corporations’ R&D departments—then let the patent technicalities be the well-paid lawyers’ problem…
Nothing truly new under the sun