Are prices really not negotiable or is this dealer pulling my leg...

I've been on a hunt for an X5 for a few months now. Every time I test drive a car that fits my specs (at numerous dealerships), they seem to fly off the shelves within a couple of hours, before I can even make a deposit. I am now on ALERT that these things go very fast -- and specifically the ones that fit the criteria I'm looking for (2021+, <30k miles, cognac/tartufo interior, exec package, etc...).

One dealer mentioned that certified BMW dealers don't negotiate on prices at all due to the competitive nature of the buy - these things will sell at sticker price. And because X5s are BMW's most salable modeL, they don't have to deal with any haggle at all.

Is that the case everywhere or is this guy just doing his "salesman" thing?

EDIT to update —-Thanks everyone for the insights. Super helpful. Was about to look into a broker when a great car fell into my lap! It wasn’t exec / m sport, so I compromised there, but I had them add the 20” 740m OEM’s on and it (instead of the 19” v-spoke 734’s) and it’s good enough for me. Happy owner of a 2023, only 8k miles, like new x5 with all the other specs I wanted — and they threw in the wheels no charge, plus a 1% discount so they did negotiate but not much. The wheels made the difference for me.