Security through compartmentalization approach actually works. Compare the number of CVEs of your favorite OS with those for Qubes OS: https://www.qubes-os.org/security/qsb/
tl;dr: Qubes security relies on Xen, which is quite popular. But even Xen has more vulnerabilities than Qubes thanks to a clever design: https://www.qubes-os.org/security/xsa/#statistics.
Security through compartmentalization approach actually works. Compare the number of CVEs of your favorite OS with those for Qubes OS: https://www.qubes-os.org/security/qsb/