"the physical burden of jet lag and fatigue" -
jet lag? longest sectors with ryr is around 4.5 hours. ezy may be slightly more having taken on some gb sectors. fatigue? some long days yes, but then still considerably less when compared to the fatigue from long/medium haul ops.
So tell us, how much "long/medium haul ops" experience do
you have...?
Apart from a few retired BA long haulers, I never met many pilots who
deliberately left a long haul company in order to 'enjoy' 4 sectors per day. The typical background in LoCo's is flight school -> turbo prop -> LoCo, with most cadets skipping the turbo prop bit and DEC's coming from some bankrupt charter airline.
If the above mentioned was true, long haulers would be banging at LoCo's doors, which is hardly the case. To the contrary, in the past a lot of LoCo F/O's have left for BA, VAA etc and have seen a 100% improvement in their quality of life.
As is often the case with lies and propaganda, if you repeat it often enough, people eventually believe it.