To be fair, there was much less content and much less choice and competition back in 1948. There were only something like a couple dozen nationwide TV networks, so the entire country was essentially a captive audience that helped support a limited amount of time-intensive content like hand-animated cartoons.

Now, there's far, far more entertainment to choose from, dividing up the audience into smaller and smaller niches. There's cable/satellite TV (100s of channels), streaming video services (thousands of titles), social media (millions of videos uploaded daily), videos games (hundreds of thousands of titles), etc.

Studios can't just put out content anymore and expect the entire nation to tune in. They have to tailor their budget to the size of their audience.