Why are most top engineering schools large state schools?

It should be noted that historically, in the United States specifically, engineering was considered a middle class profession. In Japan and Europe, engineering has always regarded as a noble academic pursuit, but in the US, the upper crust looked down on it as a vocational profession with very little upward mobility. As such, elite private universities and colleges, most of which catered to the upper class until the second half of the 20th century, saw no benefit to offering engineering degrees.

That being said, as many here have already noted, roughly half of the top 30 Engineering programs in the US are at private universities.

Something else to keep in mind is that all accredited engineering programs, like medical schools, are good. Engineering standards will be high across the board…they have to be. Engineering, like medicine, allows zero margin for error. You cannot design buildings, power plants, nuclear reactors, bridges, aircraft, space shuttles, sea ships, automobiles etc…with any errors or the outcome would be disastrous.

Another thing to consider is industry. For example, those interested in Silicon Valley are just as well served going to college at Santa Clara or SJSU as they are going to a much higher ranked program on the East Coast or Midwest.