If bike shops operate like car dealerships any negotiations will depend on several factors:

Demand. Low demand models and unpopular colors often have more wiggle room for discounts. Ask for their ugliest or least popular color. (Dark brown was very unpopular at the car dealership where I worked years ago, and occasionally the manufacturers would stick us with dark brown as part of a lot of same-model cars. Savvy shoppers, or those who just didn't care about color, got good deals on dark brown cars.)

Manufacturer incentives to sales staff (usually hidden from consumers). Some vehicle models are bundled with spiffs or minis for sales staff - either an extra bonus over the usual commission, or a guaranteed minimum commission to promote quick, no-hassle sales. The sales department might be willing to discount the MSRP more than usual if there's a good spiff. But the mini is different. It's usually attached to baseline models, like 4-banger trucks with manual shift, maybe a basic package like AC but nothing else. The salesperson may get only $50 or so for the sale with a mini, so they aren't going to waste a lot of time dickering over price, kicking in coupons for free oil changes, etc.

Shopworn or dinged models, especially new/old stock.

How much effort they put into make-ready, setups or whatever goes into the process between pulling the bike out of the carton and putting it onto the floor. Remember that sad but darkly humorous "Yeah, but that True Coat" scene in Fargo? If you know the car biz, that's a classic profit packer ploy. But unlike cars, most bikes don't arrive anywhere set up, adjusted and ready to ride. And the end result depends on the skills of the mechanic.

So, if shopping for a mid to high end bike at the LBS is anything like the car dealership, you have to play it by ear and get a sense of which models the LBS might be willing to dicker over. If you're a regular at the LBS, just ask: "Whaddaya got that you can afford to discount? I'm not picky about the color, etc." If you're not a regular they might not be willing to share that tip. Probably helps to buy a little something or other every time you visit the LBS too. Many low priced accessories have decent profit built in so it doesn't cost you much, doesn't cost the shop much effort and gives them a little bonus for giving you some of their time.