25K and 35K are by far the most numerous tiers, so why would you just dismiss them? As for higher tiers, there aren't all that many J seats on the plane. Plenty of times I've boarded with Zone 1 and seen several SEs heading back to Y. Not everyone has a company policy or the personal funds to fly J, or cares enough if they do. There are also FOTSGs who have no idea what eUps are or how to use them - concierges have told me there are plenty of SEs who will show up at the airport and just ask something like "are there any upgrades available?"

So yes, there are lots of elites, including 50K and up, flying in the back. Even FTers!