The cpu-freq applet always says "2.70 GHz", no matter what the CPU frequency actually is. Meanwhile,
$ cat scaling_cur_freq
the cpu is actually resting at the minimum.
It was not always this way. Sometime in 2017 the frequency monitor stopped being a frequency monitor.
In cpufreq menu, I've changed to individual CPU. Also, if I change to "avg" same result.
I'm almost sure this is a duplicate of bug #13835, please take a look, there's even a patch attached.
xfce-cpufreq-plugin 1.2.0 released with the supposed fix, reopen if the problem persists.