To be fair, a lot of the programs don't use a single character, have multiple spaces between fields, and cut doesn't collapse whitespace characters, so you probably want something more like tr -s " "|cut -d" " -f3 if you want behavior like awk's field-splitting.

$ iostat |grep ^nvme0n1
nvme0n1          29.03       131.52       535.59       730.72    2760247   11240665   15336056
$ iostat |grep ^nvme0n1|awk '{print $3}'
131.38
$ iostat |grep ^nvme0n1|tr -s " "|cut -d" " -f3
131.14
$