Like all fashion/trends, they are ideas & inspirations.
They're not necessarily intended to be copied slavishly.
Some people can be inspired & others can't.
Some people only feel comfortable with what they know and stick to it.
It makes life very simple if you're blinkered to all new ideas.
I completely understand your view point.

For others its a smorgasbord of options and people can taste or refuse whatever they like from it.

I doubt anyone has ever bothered to compile a comprehensive website illustrating ordinary, 'normal', safe, everyday hair cuts, but if there is one, maybe somebody could provide a link?