Does bigger/wider grid provide better user experience nowadays as 16:9 are more common?
I don't see many 960px/1000px wide layouts these times.
There is some data favouring e.g. bigger buttons, but what about whole grid/layout?
When used best, a grid is based on the most appropriate type size(s) of the typeface being used. The grid determines how many lines of text are able to fit in one row as well as how wide each body of text can be.
Within the last 10 years, larger type sizes for body text has become more common on websites in a push to improve readability (and in turn experience). Larger text can lead to larger rows and columns being required.