i suppose you can make this argument for any top engineering school, but anyway:
1. the economy is starting to pick up - the activity on the eecs jobs list is crazy. hundreds of emails a week for any possible hott tech job you could imagine.
2. there's a pretty palpable division between the business school and the rest of campus. another topic entirely, and one that's likely been debated ad nauseam on HN.
3. people at mit are not short on opinions, and some would-be entrepreneurs have trouble handling it when someone (especially a professor they respect, for example) tells them their idea won't work. see #1, rinse, repeat.
4. there's also the whole east coast/west coast theories on startups + entrepreneurship that's relevant here as well. i wouldn't say acceptance of failure is "alive and well" on the east coast.
5. the e-center at MIT has undergone almost a complete makeover (both ideologically and physically) in the past 6 months with the new managing director, and hopefully there's more to come in the next few years.