for better or worse, that's because video's infinitely easier to monetize in ways we've been conditioned with for decades. so the payouts for monetized videos are huge compared to a written blog where an ad can clutter and mess up the entire design (which loses you users, losing you better ad rates, and spirals down).

It's also a chicken and egg issue too. People simply watch more than they read most of the time. So videos target more people who gets more ad money who gets better ad rates etc.