Well then, apparently Brighthouse's fast tier is too expensive for most folks, compared to the other tiers they offer.
Charter, on the other hand, offers a reasonably-priced 30/4 tier, so people buy it because it's the cheapest advertised tier and they don't want slow old DSL.
People buy the 30/4 plan because it's the ONLY slow plan they offer, whether you want to pay that much of not!!