I'm leery of recommending amp/speaker combos since the results can vary a lot and the final decision must be personal.
But i thought I'd comment on tube life. In general you're correct tubes wear out and add the fact the decay is slow so you usually don't realize the performance drop off until you finally put new tubes in. But tube decay does not need to be as rapid as most tube amps. As an example I know Berning amps have a tube life measured in many years. They guarantee 10,000 hours and I happen to know David Berning is always very conservative with all his specs including tube life. Unfortunately while this exception exists I don't know of other examples. And Berning amps are costly and have their own sound like most other amps.