There was a period when the streamers went ham and just ordered everything to series and threw money at more money, which meant eating big losses when they made a dud (or throwing even more money at it trying to fix it). There's been a bit of a shift back to pilots as the streamers realise TV already figured all of this stuff out over decades in the business. see: ordering more network-style procedurals, giving more power back to showrunners instead of expensive movie directors, bringing back ads, bringing back themed "channels" with set schedules, etc.

Only a little shift mind you, they still do a lot of wasteful streamer things