Greg,
so something is emerging. LUBRIFICATION is the MAIN goal to be attained with a two stroke fuel. NO engine can run without the lubrication it is designed for. As for the main bearing, its need of hard lubrication is LOW ,apart from its material, mainly from the ridicoulous charge it has to bear in front of the rod extremities. Not only from its very large working surface ( I guess at last 20 times that of rod extremes, due to its longer span and wider diameter), but also from the lever effect due to its considerable lenght. So a plain crankshaft could run on somewhat resembling water, since the loads cannot break its film. LAST BUT NOT LEAST the crankshaft has the lower temperature of the entire engine, so there a mix of fluid fuel and lube HAS MORE VISCOSITY than absolute lube in the cylinder!
But here comes the unknown. Some of the oldest engines preferred ether, IT IS A WONDERFUL CHOSE by the point of view of the lubrification. Probably the ENTIRE inner engine runs on straight lube, maximizing compressibillity and durability.
But there are some tradeoffs, since ether is rather a " monochrome" fuel. IT IGNITES TOO EARLY AND TOO CONTEMPORARILY, giving the less diesel shape to the pressure cycle. That is the less power, you know. AND AN ENGINE RUNS ONLY ON THE PRESSURE CYCLE!.
So we need balancing somewhat in HCCIs fuels. Kerosene helps...but does it evaporate sufficienly in ours?. THIS IS THE CONUNDRUM, POWER VERSUS LUBRIFICATION. And I strongly feel that not all it is done in fuels for having powerful and LASTING engines.
THE FIRST REAL ECONOMY is the DURATION of the ENGINE, NOT THE COST OF THE FUEL. Rather easy to assess if you evaluate how many liters of fuel is lasting an engine...not to say the old irreplaceable pieces of art some fortunate can enjoy running also today!. Of course this reasoning does not hold for extreme users. A worn engine may be well worth a championship!
In this way I agree with you not to follow purposes and ways out of real model HCCI (aka diesel) needs, following what is done for extremely different engines with totally different purposes. But I don't agree with the "stare decisis" you seem to prefer, but not to practice when you investigate on our engines.