That canard is getting old.
These days I can easily give each user a separate server, even several servers. They are freakingly cheap - I can buy decent compute nodes for a $5k apiece (and it's going to be much more powerful than a mainframe partition of the same cost). Sure, there's also the question of shared storage/database, but that is also readily solved by a multitude of NAS/DB vendors. About administration costs - it's very hard to find mainframe specialists. So just their salary can outweigh every cost advantage of a 'single' mainframe system.
I actually don't really care about manufacturing quality as long as it is good enough. I feel that we should design systems that can tolerate failures rather than trying to design infallible systems.