What about everyone else? Many companies only operate a handful of servers, and they often don't have the staff to know the kernel that intimately, so they rely

What about everyone else? Many companies only operate a handful of servers, and they often don't have the staff to know the kernel that intimately, so they rely on sane defaults. These companies are also not typically using their CPUs to the max, so disabling HT seems like a reasonable default. If you know enough to know whether up should be using HT, you can enable it yourself.