Some organizations don't allow it by company policy, regardless of whether it can be installed.
Anyone care to enlighten me as to why?
Large organizations, particularly those which train non-IT workers to follow consistent workflows like to avoid any changes. Chrome Frame was great because it was a minimally disruptive opt-in for a better web; Chrome for Business requires you to switch to Chrome for everything and whitelist legacy apps/sites – that might happen if someone at the C level is really scared about security but it's way more risk and the shops in question are among the most risk averse.
I think its time enterprise I.T managgers update their thinking, and I think the less comfortable backwards compatible tools that exist, the better.