I don't think it's anything to do with being frugal. Buffet said many times during the dot-com boom that he wouldn't touch a tech stock with a 10 ft. pole owing to the fact that he had no clue what any of them did. When the bubble burst he had one of his best years ever by investing in brick and paint companies, IIRC.
So, it's not that he won't spring for a post-1992 web site because he's cheap. It's because he couldn't care less about the internet. He doesn't even have a computer. In a way I'm shocked that berkshirehathaway.com even exists. I assume they bought it to keep some idiot from hocking Viagra under that name.
To me, the world's richest man completely ignoring something to which many of us here devote our lives is a great reminder of the whole other physical world out there which will always be equally, if not more, as important as tech. Microblogging, blah blah will come and go, but people will always need to build brick walls and paint them.
there's this funny bit in The Snowball, where Buffett suggests to his wife that they let their daughter sleep in an old dresser drawer versus buying a new crib.
Just because the developer is offering his services free of charge doesn't mean it's free to the company receiving said services.
Just one meeting with Warren Buffet to approve the website redesign would be the equivalent of thousands of dollars (people pay in the hundreds of thousands for lunch with him). Additional disruptions in the already small corporate office would incur additional costs.
