I used to work at ESPN.com. My job application was a proof of concept of a similar idea, but because it was 2002 and wasn't possible to build technically it was designed to show that I could code and think creatively about consuming sports online.

When I took the job, the realities of licensing footage hot hard: the leagues were not keen on letting a third party like ESPN have historical, searchable footage like this available on demand. The leagues were still figuring not how to make money from digital and rights to their games are the biggest asset they have.

Things have changed since then but the tl; dr is that from 2002-2005 the reason this wasn't built by ESPN was not technical or due to a lack of imagination, but a business reason - it was prohibitively expensive / impossible to get licensing rights from the leagues.