I know this sounds remedial, but in 30 years of riding I have never bought a bike at a dealership lol.
No shame, despite the posturing by some... we all start from zero.
I found a 2015 DL650 brand new at a local dealership. They knocked $2500 off MSRP and asking $7900 - but I think it is still priced too high.
MSRP is meaningless, it is a negotiation anchoring price in their favor and, yes, way too high.
There are Gen 2 DL's all over the internet for $5k.
That is the proper negotiating point. That 2015 has been sitting at the dealership for 4-5 years. Apart from a wreck, sitting for years is the worse thing you can do to a bike. You'd be better off buying used or a Gen3 if you want new.
I had a 2007 DL650 (Gen1) with 90K miles and upgraded last year to a used 2014 DL650 (Gen2) with only 3K miles for $5K with well over $2K in upgrades (that I wanted or could sell). I did not know at the time but Suzuki botched the redesign. Get the Gen1 or Gen3, PM me for details.
What is the profit margin when the bike has been sitting 4 years? Would they take a loss at any point? How does surplus inventory hurt their bottom line?
This is none of your concern. Their asking price is comparable to what you could pay for a Gen3 which is a better bike and much higher than a fully-farkled, used, low-mileage Gen2 bike for $5K. As others have suggested, you could low-ball them (relative to THEIR price but not the market) and see if they bite. $6000-ish OTD (out-the-door, i.e. including tax, license, dealer prep, etc.) for a new, bone-stock Gen2 2015 wouldn't be the worst deal but a) they probably won't do it but it never hurts to ask b) for $9K-ish you could have a new Gen3 and c) you could find a better deal for $5K on the used market.
Also, these are budget (but good) bikes and unless you have money to burn there is no reason to buy new and a Suzuki warrant isn't worth that much anyway which is all your really get buying new.