Trouble finding Wills

[steviedresdonian]

Apologies, as a newbie if this is a stupid question, but I know that I can search UK wills via my Ancestry subscription, and I can also search for wills/probate records via https://probatesearch.service.gov.uk/

But should there be a will or a probate record for everyone who has died?

I can't find any record of a will or probate record for any of my grandparents or great-grandparents (who died variously between the years 1944 and 2014) - am I missing something?