I'm a little surprised they don't do something like iOS does for rendering list views quickly... have a small subset of item views rendered and basically reuse them. You aren't displaying all 7,000 items so while maybe it makes sense to load the data in one shot, does it make sense to load all the DOM elements? Probably not.

Also, I understand why things get slow, but I will never understand why performance benchmarking doesn't seem to exist in many places as part of the QA process. Writing tests and making things work right is usually there, but making sure things are performant and the user has an outstanding experience seems to get left until it's a "problem".