The thesis is fine, whatever, but do they actually prescribe a solution here? What can someone do to "design for a long lifetime"? What does a website that is "

The thesis is fine, whatever, but do they actually prescribe a solution here? What can someone do to "design for a long lifetime"? What does a website that is "designed for a long lifetime" look like? This all very hypothetical. My personal site is dead simple, about 20kb uncompressed (50-odd pages), and uses semantic HTML, minimal CSS (~2-3kb) and no JS. But that's for simplicity and to keep my costs down. There's no saying whether even this basic structure will be supported 20 years down the line because it works on browsers now.