What is it about certain designs that give them a 'modern' look despite the passage of time? Do sharp, angular lines always suggest a 'modern' or 'contemporary'

What is it about certain designs that give them a 'modern' look despite the passage of time? Do sharp, angular lines always suggest a 'modern' or 'contemporary' aesthetic? What makes a design feel dated or old? Here is a teapot design. Modern-looking? (Some of you may recognise it.) Can you guess when it was made? https://media.vam.ac.uk/media/thira/collection_images/2006AB/2006AB1456_jpg_l.jpg https://media.vam.ac.uk/media/thira/collection_images/2006AB... Here's who designed it and when: https://collections.vam.ac.uk/item/O78328/teapot-dresser-christopher/ https://collections.vam.ac.uk/item/O78328/teapot-dresser-chr... Some more designs by the same designer: https://www.liveauctioneers.com/news/wp-content/uploads/2015/07/2015_0709_Dress-2_3.jpg https://www.liveauctioneers.com/news/wp-content/uploads/2015...