Why would that make a difference? We're not talking about manufacturing defects, every single unit they sell has the problem, doesn't matter if they sell 10 or 10 million.
ARM is actually a good target with a number of their newest designs using out-of-order speculative execution with Spectre vulnerabilities and their owning mobile space outside of notebooks, one of the newest even being vulnerable to Meltdown, but the significant headline worthy instances tend to come in much more locked down devices. Speed is also an issue, everything else being equal, the faster the chip, the faster data exfiltration proofs of concept will work.