I remember Dragon SpeechDragon Naturally Speaking saying the same thing in the 90's. It's improved, but not enough to make it useful as more than an aide for people who can't type. I do agree, that for simple accessibility, it should be integrated into every field, but I doubt it's ever going to take over.
As others have noted, that it's only technically true that dictation is faster than typing. In a practical sense, there's a fair number of reasons why that's not the case, including that usually thinking about the entry is what's the slowest, and also the errors in both are typically what slows people down.
there's also the problem of, for example, keeping entries confidential. You don't want to speak your passwords where others can hear you.