It's cheaper to implement than HDMI. So if DisplayPort ports are common on displays, devices will start using it (cheapo devices first). If DisplayPort ports are common on devices, displays won't need HDMI anymore. Plus, industry-wide, it's wildly inefficient to have one high-bandwidth video connector for monitors and a different one for TV's when the technical distinction between those is pretty much non-existent and we could scale our engineering effort across a much wider set of devices.

So, after a transition period, cost-saving will eventually lead to DisplayPort taking over.

Because the manufactures don't have to pay a license fee and so once someone start using it everyone will follow and then drop hdmi. However so far nobody has cared enough to be first.

USB C is at least one reason that will apply constant pressure.

Well, if this were a free market, b/c there would be demand for it? I want a more standardized protocol so I need less cabling and connectors, and I want features like 4k that HDMI effectively (see TFA) does not support.

I would vote with my wallet … if I could.

Like, why do we need two connectors, for the same thing? DP is clearly technically superior.

Of course, there's a wide range of issues: there's a number of comments on this article stating how the HDMI forum is manipulating the market (e.g., by suppressing competitor connectors on the board, offering lower royalties for bugs, suppressing specifications), and then there's just getting out-competed by the litany of consumers who have no idea and do not care to know what they are buying, and marketplaces like Amazon that promote mystery-meat wares.