Will it last another 25 years?... probably! E3001 only had about 6000hrs on the clock when it was converted to the Met research aircraft, the fleet leader has nearly 50k on the clock. The last RJ was delivered only two years ago so it's likely to be around for a few years yet.
Pity it was such a political toy and the money that was spent on it's later development didn't solve some of the basic problems. It's certainly kept me in work over the last 20 years and it's always nice to see E3001 as I spent many happy hours looking after it at Woodford.
DC