The masses don't give a shit about whether something is scientific or not, so mythbusters has to be entertaining to gain a wider audience. If may not be the type of scientific rigor that is required in a lab, and it may not be scientifically proving anything that scientists in a lab care about, but they are showing people that you can take generally accepted "facts", put them through a scientific stress test, and then draw conclusions based on the data. You cannot create an entire civilization of people who accept science by simply forcing down the most extremely rigorous testing methods down their throat. The masses need to be entertained while they learn, and Mythbusters does a damn fine job.