a) Some companies (Toyota?) treat their employees well enough that they don't feel the need to unionize. Toyota (among others) isn't unionized, so it sort of suggests that your thesis that employees are 'terrorized' into joining unions isn't quite correct. 

b) Wages set at Toyota are partly set by the wages negotiated at unionized auto plants elsewhere. 

c) Go check out the wages paid to workers where there are no unions, to get an idea as to what a completely union-free environment looks like. Go check out Call Center wages, for instance. Or what part-time instructors get paid at community colleges compared to full-time (unionized) instructors. And I'm sure there are a lot of other examples.