This wasn't for breast pumps, it was for fetal monitors.
Fetal monitors exist in a fractally broken market. The people delivering medical devices have little motivation to be price-conscious because the people making purchasing decisions about their products have limited motivation to be price-conscious. The people making purchasing decisions have little motivation to be price-conscious, because they just pass the costs on to patients. Patients, in turn, do not ask about costs associated with fetal monitoring up-front, are not in a position to do any negotiation regarding fetal monitoring in the moment, and in any case aren't too worried because their insurance company picks up the cost. Sort of. The insurance company, in turn, doesn't worry too too much about the cost of the fetal monitors that the hospital chooses, because they still figure out how to pass the cost back to the patient - which they can do successfully because in the United States it's exceedingly rare for consumers of health insurance to comparison shop. Instead, they just go along with whatever option is chosen by some HR folks who are mostly spending other people's money and therefore have all sorts of incentive to not worry too terribly much about the best interest of the consumer.
So yes, there is some weird consumer psychology at play. The weird psychology is that we've got this crazy aspect of our culture where it's not just OK for our employers to be meting out important and expensive health care decisions to us (a bizarre proposition if you look at it objectively), it's actually desirable, so desirable that many people are unwilling to consider taking jobs where a health plan isn't included in the benefits package.