Why do some products don't reveal their pricing on their landing page?

Because they haven't figured it out yet and are willing to let price fluctuate. Whenever I don't see pricing (save Enterprise pricing) I always assume one of three things: 1) They havent sold enough to understand the value of the product, as perceived by customers when they experience the product 2) They are in a market with limited competitors and they dont want to easily show competitors their pricing 3) They sell on the fly and are willing to drastically reduce the cost right before signing

Potentially yes, if the pricing is on point, but on the flip side if a company hasn't yet nailed it, having it listed can end up in people not even engaging and never returning. At least by hiding the pricing it gives the organisation some wiggle room once someone inquires. A good sales person will understand quickly who they're selling to and adjust the price accordingly to get the company the best price, whilst ensuring the deal isn't lost.

Often B2B products won't rely on landing pages for sales. Instead, they will reach potential customers directly through reps. The website is just a perfunctory thing in this case. Might even harm you to put on the prices