Your list of the process isn't entirely accurate (though most go for all the above to be safe). I dabbled in this many times before I was successful and even with doing everything "right" I only had a 60% chance on Aztezul.

We've seen some extremely long lived necromancers get to 80-90% base chance but even with them factored in there's still more people failing than succeeding.

Not to mention getting the items is often a nightmare. I've seen some of the best PVE players fail miserably to find a third/fourth item. I've seen some of the same players identify their item and never have a group strong enough to get it. Do you know how many items live deep in Yzekon, for example? It's more than a few.

The reason there's no liches is the imms don't have the time to spend. Lumping mummies into pile is just going to ruin another class that was already badly hindered by the edge point changes imo.