All other comments not-withstanding, there has been an inflation of education. The underlying cause is that there has been an inflation of knowledge.
In the 1800's, to get a bachelor's degree nearly meant that had a relatively deep, contemporary knowledge on all or most matters of human experience. Now, a Phd means that you have a good background knowledge of 1 subject, complimented by indepth knowledge of one specific research question within that field.
Vocational training exists because of market forces. Companies can in essence pass off the cost and risk of training an employee. They can then hire a pre-trained employee. The company benefits by having a more efficient work force. The employee benefits through higher starting wages.
People who do not want to go to college have no good reasons to do so, all things considered assuming they can accurately assess their own future priorities in the present. People who do want to go to college have no good reasons not to, all things considered. It depends on the goals and desires and how likely one is to be able to predict their future desires. I think it is safe to say that very few people truly view their college experience as a complete waste. It may be an economic waste but a valuable life experience which bonds them with their cohort of friends and family. In general, the JW's are criticising college because they believe...
1. The desire to have a career which is meaningful or which supports a wealthy lifestyle is superfluous or immoral.
2. College itself is used by invisible supernatural powers to ensnare people.
Both of which have nothing to do with the question of whether college delivers as promised. I will want my children to go to college and graduate school. I wish I would have been free from the pressure to under-sell my opportunities. This I will never forgive the JW's for. Everything else I don't really care about too much. There were things I could have done and wanted to do, but I didn't with great sadness out of a false sense of duty.
Even in the trades there is a tendancy toward consolidating under larger businesses which are more profitable. Look at the big publicly traded home builders, for example.