diesel research, you are so right.
Specialty tools are always expensive. I have some of the ones for one of my own cars, and they're expensive and made for a single engine model. Want to change the cams or pull the head? Plan on spending over $1000 in a few specialty tools. This one lists for about $600, and is only one of the tools needed:
Without it, the odds are good you're not going to get either camshaft installed correctly and will damage expensive parts.
These tools also tend to go out of production fairly quickly just as you stated, which means if you don't buy them fairly quickly, you may never get them and may hence never be able to do the work they're designed to do, or at least won't be able to do it right (and risk damaging parts that might be no longer available or very expensive). The tool above was not available for a few years, and they recently made a small run (with a new design; the original had 2 push-down arms versus 4 in the new design). And as the stock of them dwindles, the price goes up, at a much higher rate than any mutual fund and most individual stocks. Same deal for many of the parts, especially on a low production vehicle (and an AMG would fall in that category). My center console was originally about $1200. It's now about $7000 if it's still available. On a vehicle with high production numbers, you can junkyard dive with some success. Not so much for a vehicle whose production numbers were a few thousand worldwide.
Same reason my car never goes to the dealer or an independent for service (except wheel alignment). The risk of damage to NLA parts is too high for me. That's fine with me since I enjoy doing it myself.
To the OP: good luck with Hazet, hopefully they'll just give you a new socket.
Hopefully warranty replacement via A&E Hand Tools (the North America Hazet distributor) will be smooth.
by you or the MB dealer 
Just watch the video he posted of the un-heat treated hazet wrench bending like a pretzel 
