We do try to avoid long concerts and late finishes, for example by starting promptly, keeping the interval short and avoiding encores. We changed the starting time from 7:45 to 7:30 and no longer serve hot drinks during the interval for these reasons.
We could reduce concert lengths even further by reducing the number of pieces, truncating pieces, omitting introductions, not having an interval and so on. We have occasionally done all of these things, but if you think we are striking the wrong balance please let us know.