A lot of the time, there is a particular individual who has the cheque-signing power up to $X. For such a person there is a psychological distance from the act of spending -- it's not a personal loss if the purchase doesn't pan out. Whereas for individuals spending their own money, the simulation heuristic makes purchases of unexperienced goods or services much scarier.

Hence my "monopoly money" remark.

I think you have correctly reflected that a purchasing decision may have input from many different parties. But these people matter from a sales perspective only so far as they influence the decision of the person with the chequebook.