Now, unlike your claim, others were in production under label MILS systems far back as 2005. They used separation kernels to host VM's for Linux and Windows with networking, filesystem, GUI, etc in separate partitions plus color labels on screens. Sound familiar? Additionally, the Turaya work in Europe got turned into commercial products from Sirrix. OKL4's was deployed in a billion phones. Genode's tiny team has made theirs quite usable in short time despite all the custom work done.
So, Qubes wasn't the first, most polished, most secure, least academic, or anything. It's a latecomer using inherently bad components but with high usability and tolerance to regular malware. There's an upper limit to how much security if can provide as malware sophistication and threat model increases. So, I encourage its use only for lower, threat profiles like average user browsing the web with investments into stronger architectures for higher, risk use.