content: Besides what @Caesarkid1 mentioned, a large part of it is actually being able to build a neural net of sufficient size without the thing needing terawatts of electricity. Computers have gotten a hell of a lot faster over the past decade, and compared to what they were in the optimistic, halcyon days of early AI research they're... well there really isn't a comparison. Compare a 1925 Packard with a Dodge Viper.