That smells familiar. I worked with one of those wizards and he designed everything to keep him the job. That was until he rode a motorbike into the side of a car at 100mph and someone else (me) inherited it. I had to start again because it was that impenetrable. Consequentially it turned out it didn't do a lot and I'd rewritten the bulk of it in ASP/SQL Server at the time in a couple of weeks reducing the cost of the entire platform to an hour or two a week rather than an entire "tier B" (whatever that was but I was told it was a lot and was tier F myself) salary. When I quit it took a few hours to hand over to the next guy.
Indeed, the word wizard was perhaps ill-chosen. These guys know this particular codebase, in all it's hairy glory, but not much else.
The the multinational decides a change in direction and fired the entire office, relocating it for regional diversification (this was not offshoring, spreading the work out across multiple teams). This was pretty niche stuff, and he became unemployable until moving across the country.
And I know of a company that similar was outsourced to. Fully outsourced with seemingly no internal expertise. Bleeding their client for increasing support prices year-by-year imagining they could do this for ever. I was in the team in that client that for two years, going from-scratch re-implementing the functionality, no cheap proposition, but within 3 years of in-sourcing the savings were already there.
Not all wizards know magic.