I don't see it as a published limit, but a limit of 1000 is a pretty common limit with Quickbase for various unrelated features when they need to set a reasonably high but somewhat arbitrary limit when they can't support infinity.
I'm not sure if your stock price example was a real one, but you could group by Weeks instead of by days, and use an average.
Or else maybe you can line up multiple graphs on a dashboard page side-by-side for different time periods relative to the current date. For example, a chart for the current and last year, a chart for two and three years ago and a chart for four and five years ago.