Mostly they're designed to get you to pay for a subscription and then not actually get many dates, rather than to help you meet people. If you actually meet someone you stop paying for the subscription and the company stops making money from you. But if they can string you along indefinitely on the idea that you might meet someone, you keep paying. It's a perverse incentive, a private dating company only makes money if their product doesn't work.

part of the problem is that a lot of the swiping apps were at least partly inspired by Grindr. Grindr had a different audience - Gay men who wanted a hookup - and a different goal - helping gay men find a quick hook-up. Guys using Grindr weren't likely to stop using Grindr when they found someone to hook up with. Grindr was more appealing to it's audience the better it got at helping them find hookups. Tinder et all had a different audience - heterosexual people - of whom some were looking for hookups, but many were looking for longer-term dating. Trying to apply the Grindr model to straight (and other) people seeking relationships didn't work as well, so capitalist innovation kicked in and they started searching for ways to manipulate people in to spending money on a product which by necessity couldn't do what it claimed to do and still make money.