Absolutely correct... The very same design lifters work just fine in other applications. Lifters work just fine in an EVO! As Don said, it's the overall system - the lubrication, forces, angles, pressures, temperatures and so on... The Twin Cam package is plain not conducive long lifter life. No one factor, probably no two or three factors. The entire package. If I were one thing, it would have been solved by someone a long time ago...
Just like the compensator. There is no magic compensator design for this package. Compensators work just fine in lots of applications, but not in this overall system.
Which, looking at it from a design perspective rather than a pissed off owner's perspective, is actually interesting as to the product and informative as to the company.
Lifters didn't fail like this in earlier Twin Cams. Sure, cam bearings did (early on) and chain tensioners did. But not lifters. The cam bearings especially were a component rather than a system issue too.
Then Harley took an engine designed to be (with some basic adequacy) a low horsepower 88 inch engine and thought they were smart enough to make it both larger and weaker at the same time. Timken bearings and reinforcements went away, crankshafts became less robustly manufactured, geometries and pressures became more challenging and displacements and outputs went up.
The only band-aids were compression releases to help with starting (and nothing else), a grossly ineffective compensator system (to minimize crank issues that would otherwise likely be even worse) and a little water running through the heads. The system was adequate (not great, just adequate) enough for what it was. It is still, basically, a decades old design that they are now trying to limp in to the 21st century and compete with companies producing more power. It's no wonder the damn things die like ants in a playground full of boys with magnifying glasses.
There is simply no way Harley didn't know this was a questionable recipe with weak ingredients. MoCo is in the enviable position of selling vehicles that don't get many miles though. So they can get away with a LOT that other manufacturers would not. As much as we hear now; think what the tumult would be if this was discussed over an actually large fleet that regularly got 100,000 miles in 6 years?