There wasn't a lot of widescreen content before HDTV sets came out. There were still TV shows as late as 2008/2009 still broadcasting in 4:3 despite there being widescreen TVs releasing a decade earler, and 4K HDR content has only really become a thing since the TV manufacturers decided that 4K HDR was the next big thing. I'd say it's a chicken and egg thing, but the content providers will never make ultrawide content if there isn't a screen for it. The problem with Philips' attempt at ultrawide TVs is they were the only ones doing it, which immediately doomed it to failure.
If the TV manufacturers agree that the next big thing they will push is ultrawide, the content providers will make their way there. But this is entirely up to the TV industry, who are notorious for slowly trickling out features people want in order to keep their annual TV release cycle from feeling stagnant.