It depends on the people you’re playing with. With an active group there’s a lot of strategy that goes into the negotiations, and also a good amount of “push your luck” gameplay. In my experience, a lot of the game comes down to one or two extremely intense negotiation sessions that everyone at the table ends up jumping in on.
It also depends on the rules you are playing. Monopoly is a game that most people learn not from the rules but from family and a lot of families have very different house rules.
The in the box rules state that every property must go to auction on first landing if the player refuses their option to buy it at face value. There's a lot of strategy possible in auctions, but a lot of house rules don't like the auctions and either avoid them entirely or make them much rarer than the in-box rules state they should be. (In part because early and often auctions increase the cutthroat feeling earlier in the game, whereas a lot of house rules are about pushing the cutthroat stuff off later into end game.)
True. You also need a group that knows what they're doing and is trying to be cutthroat. Then the whole table is trying to trade for color sets and dissuade others from trading for color sets, which often leads to this absurd mass negotiation where people are just throwing away massive amounts of money and property in order to not be shut out. Sometimes you end up bribing another player just to keep them from undercutting a deal, or you work with that player and cut out the original person you both were haggling with, at which point they're trying to bribe another player to intervene.
As long as you're using the correct rules and everyone is playing the game fast, they know what they're doing, and they're competitive, the game can be quite fun. It's also a lot less time intensive than many other board games where lots of people are negotiating.
Also important is that the supply of money, of houses and of hotels is fixed.