As an aside, I'm always surprised how US Gov websites look like they've been made in Dreamweaver in about 2006. Not even seemingly with a emphasis on usability either.
The ones that look old are old. The USG has newer design systems that you'll see used on many of the websites that have been redesigned more recently: https://designsystem.digital.gov/
This admin gutted both NOAAs budget and workforce so a website redesign is probably low priority at the moment.
You can thank AccuWeather for nerfing any funding for site modernization. I'm surprised the tiled radar map hasn't had the Biden performance fixes reverted.
Why must everything look and be modern
While it may not be flashy, I personally find the GOES sites extremely useful. Things are often simply placed at obvious and expected URLs, so scraping or monitoring is extremely easy.
I wrote the script that provides the GOES NavSum [1] and it pretty much just builds a standardized text file and drops it in the folder. The neat thing is that this makes it really easy to programmatically scrape and parse the data.
I wrote a personal script at one point that would download the GOES-EAST CONUS image and both EAST and WEST full disk images and composite them into a wallpaper. At one point my server had 500GB of archived GOES imagery. I liked to joke with my former coworkers that I could report image anomalies before they notice because my desktop wallpaper would change every 10 minutes.
[1] https://www.ospo.noaa.gov/resources/cemscs/navsum.txt