NO listening fatigue, period. THAT is one of the important tests for "forever" speakers.
Try that with ANY OTHER box speaker, electrostatics, etc. Unfortunately, you will want to stop listening to any other brand eventually. Never true with Maggies unless your source material is unlistenable. NO speaker fixes that!
Also, they reproduce what you send them. If you can live with that, your quest is over.
As an owner of Maggies I must say this is a very misleading post.
It’s true that Maggies require good gear to get the best from them but they have their limitations and are far from perfect. Many speakers previously mentioned are more resolving than any of the <$5K Maggies, regardless of sources and amps. A good example is the Spendor A4 and likely even the OP’s LSAs. The Magnepans certainly have their strengths but ultra high levels of detail and pinpoint imaging are a couple areas where they fall short compared to many in the $5K segment.
And of the three Maggie models I’ve experienced (1.7i, 3.7i and .7), for whatever odd reason, only the .7s offer a balanced presentation with real bass slam. The 3.7i do indeed produce fatiguing highs, while the 1.7is must be cranked over 80db to get any real bass dynamics, and lack resolution.
Where all Maggies seem to excel is disappearing as sources of sound and transient speed. For those reasons I love my .7s but like any speaker, they’re not an end-all, be-all. Some of my <$5K box speakers can throw a much larger soundstage and showcase greater detail.
