Let me put it the way I see it:
- you lease your vehicle from dealership, but signed contract and paying directly to head office financial branch
- dealership has no power to change anything, including buy-out numbers
- at the end of the lease you have few options: walk away, buy-out and las one - do appraisal and in case if dealer give you offer to buy your car for more, than contractual buy-out number, you may have positive equity towards lease/purchase of new car at the same dealership.
Therefore: buy-out number are not subject to adjustment or change at the dealers level.
Let's look at the 'Current market value'. Manufacturers do their best to plan ahead and predict sales volumes, depreciation, demand, etc for all models for years ahead and based on this they establish prices, discounts, rebates, interest rates, and - lease buy-out numbers.
There are cases when for specific (good cars in demand) models you can get positive equity, but in most cases - no.
So when dealer sees your nice car, they may offer you better number than buy out (knowing they will be resell it with good margin), plus opportunity to sell you a new car.
The bottom line is: there is so called 'deal zone' - the area where the deal is possible, but quite often dealership is not sharing benefits equally, but pushing line to the area where they getting most benefits.