So my 2 cents...I raced Legends years ago and for the last 10 years Super Lates. Still have the SLM and will still race it occasionally, but last year bought a Legends to put some fun back into racing. So I have experience with all types and all associated costs.
This discussion is only productive comparing apples-to-apples. A race-ready Baby Grand QC rear assembly, including axles and a gear set is in the neighborhood of $2,070, and each additional gear set is $70, so with (1) spare sets of gears you're in for about $2,140. For Legends, a new double-shear housing, with new axles and a fresh spooled gear is about $1,400. Add only 1 additional gear set , and you're in for a little over $2,000. Pretty close to the same.
Add a 3rd set of gears and the total investment in the QC becomes $500 cheaper, and for each (1) additional Legends gear set, you can buy 7 or 8 QS sets.
On straight economics, I pick QC every time. That doesn't even take into consideration the time and ease of changing gears. Or ease of storage. Or yearly maintenance.
Not saying it should happen, but the option would be nice, especially given that Winters has the race-proven parts in their standard catalogue. Cheers, Tim