I'm not sure what point you are trying to make.
Yes, if an element width is set to say 200px, it would take up virtually all the available width in a screen only 300px wide and take up much less space, relatively, in a screen that is say 1200px wide.
You could set the width to percentage units to make the element width "elastic" if you want so that it expands and contracts with the browser window size.
But you would have exactly the same issues with tables if you want to specify a width for the table.
I don't like using tables for layout, because the markup code can get very messy, large in volume and difficult to maintain very quickly - especially if you use nested tables.