Not to go toooooo far down the rabbit hole here, but even that is a "kind of".

Specifications can (and often are) written in a way to limit potential bidders. Lets say there are three manufacturers of these things that have good build quality, but I want to target a specific manufacturer. I could put in specific upper and lower constraints for height, width, flow rate, etc, and then I can say that due to the site conditions (which were designed to those criteria) only one manufacturer is eligible.

I can then add specific restrictions for installation certifications, warranty coverage, distance requirements for eligible servicing personnel, etc.

While all this may seem reasonable and practical in the spec, its really just a way to control who is eligible for competing on the bid.

And if I was really shitty, I could leave specific things ambiguous so a company can come in really low on the bid to get picked, who then issues a change order because of that thing. Which then makes the cost higher than the losing bidder who included it from the start.

Its not really as competitive as you think, thats part of the disgusting game being played.