I think d'Apps (Decentralised Applications) originated in the Ethereum Blockchain thanks to smart contract technology that was first implemented there but due to slow speed and outrageous fees when the ethereum blockchain is overloaded, most d'Apps started migrating to the EOS Blockchain because it was lightening fast and has very very cheap fees but due to the recent spam attack that has lasted close to 2 months now on that blockchain, most active d'Apps has started migrating as well to other more conducive blockchains or side chains because the EOS network is now close to unusable at the moment, it would cost a lot of EOS staked to make a single transaction daily and it's just not conducive to d'Apps at all where users sometimes makes thousands of transactions on a daily basis.

But I believe that when the perfect Blockchain infrastructure is invented, d'Apps would still be the king and would reign supreme.