I have yet to find a titanium bike that cracked from fatigue failure, with the possible exception of the Merlin Extralights that supposedly cracked at the bottle bolts from the tubing being too thin.

The fatigue limits of Ti alloys is simply better than chromoly, and then you have to the flexibility, which means that Ti used in bikes with oversized tubing isn't flexing anywhere near its yield compared to steel.

For similar reasons, greatly oversized aluminum frames, like Kleins, are also unlikely to to succumb to fatigue because no part of the frame flexes much at all, so despite aluminum not having a fatigue limit, something so rigid is also isn't going to fatigue a lot more than it would hanging in the garage.

The hubris is not that the materials aren't going to last, but that the welds are all perfect enough to never be contaminated. But I don't think that is really hubris as much as it is a way to convince the cycling market that 3/2.5 bikes (and later 6/4) had turned the corner from Teledynes that seemingly all broke. And I doubt the total number of warranty repairs or replacements have damaged Litespeed before or after the sale.

If lifetime warranties were a problem for Ti bikes, why would the companies with the most experience making Ti bikes still have them?: Lynskey, Litespeed and Seven all have connections back to 1986.

Some Asian builders just aren't doing the sandblasting or polishing to keep costs down. It isn't like the weld is dirty. I imagine some people like the colors.