What are some examples of individual ministerial responsibility being weakened?

In 2020 Gavin Williamson approved an ofqual algorithm that downgraded thousands of students across the country and didn’t resign. Chris Grayling seen multiple failures in his department such as awarding a ferry contract to a company with no ferries and a leaked letter showing his dubious reasoning for opposing the end of Southern rail franchise. Priti Patel refused to resign over a cabinet enquiry that uncovered evidence of her bullying staff.