The Chrome team doesn't want to support multiple distinct Linux binaries, so they drop older platforms once library versions skew enough to cause this. (This page claims it's libstdc++: http://chrome.richardlloyd.org.uk/ .) I think the Chrome binaries are built on Debianish systems so it's always a small miracle that the RPMs work anywhere.
(Why only support one binary? There's already a disproportionate work_required/users_served ratio for Linux vs the non-Linux platforms even with a single binary, and multiple binaries would mean multiple nonmatching stacks in crash-catching and a more elaborate testing matrix. You can find Chromium builds of the equivalent code that are built with the appropriate toolchain for your platform anyway.)
Disclaimer: I worked on Linux Chrome many years ago, all of the above is just guessing based on what was true back then.
Which makes total sense of course. However, if you're going to choose a limited set of Linux distros to support, it seems like RHEL (and thus CentOS and Fedora) would be a good choice. There are lots of companies paying money for the supported version of those distributions and are compelled by corporate security policies from upgrading various components to them at will.
In a joking-but-actually-kinda-not sense, the only justification for Linux Chrome existing is so Google engineers test the websites they make in the browser used by Google's users. So the only Chrome they really make is the one that runs on the engineering workstations. (On the Linux team I liked to joke that 80% of our users were coworkers.)
(Why only support one binary? There's already a disproportionate work_required/users_served ratio for Linux vs the non-Linux platforms even with a single binary, and multiple binaries would mean multiple nonmatching stacks in crash-catching and a more elaborate testing matrix. You can find Chromium builds of the equivalent code that are built with the appropriate toolchain for your platform anyway.)
Disclaimer: I worked on Linux Chrome many years ago, all of the above is just guessing based on what was true back then.