Verbatim 2.4x DVD+RDL really is not an 8x capable disc. It's great at 4x, and even pretty good at 6x, but 8x is pushing it too far. This is not just MY opinion, but even Verbatim's opinion!
Yes, some drives like the Pioneer DVR-110 can burn MKM001 at 8x. And some individual drives of the DVR-110 can even do it well (same goes for the DW1640), but a lot of individual drives can NOT do it well, as shown by Ian and my reviews, as well as various user tests.
Now I don't agree with restricting MKM001 media to 2.4x, I think that's actually quite stupid, because the best quality results often occur at 4x recording, but I don't agree with it being burnable at 8x either.
As for "forcing" people to buy more expensive media. Do you REALLY think any DVD Burner really cares about making sure you buy some completely unrelated company's newest more expensive disc? They don't care at ALL about it. They have no reason to care about it.
Punch Cards -> Paper Tape -> Tape Drive -> 8" Floppy Diskette -> 5 1/4" Floppy Diskette -> 3 1/2" "Flippy" Diskette -> CD-R -> DVD±R -> BD-R
The Progression of Computer Media