How many MPs , recent PMs and Minsiters would actually get through these processes are they vetted at all. I went through the DV process in a previous job and it was pretty thorough although it only tooka few weeks -around 2000.
Also as has been pointed out concerns about potential technology interception by people from the east might increase the need , also ensuring confidentiality by people doing the same things in UK already.
Seriously though would Johnson have passed if he wasnt PM ??? how many children do you have -- err umm err.
In a vaguely simialr vein a lot of media comment about Govt esp MOD deny access or involvement in public events because of their views on issues not remotely connected to the activity itself, Thats real Stasi stuff