You got trained while you worked because most people stayed at the same company from the day they started until the day they retired. So it was easy for companies to justify investing time and money into training: barring unusual circumstances, they expected that person to remain an employee for a long time.

Nowadays though, job-hopping is the norm. If the company cannot expect you to stay for longer than X years, they're going to adjust their hiring practices to make sure new hires are "safe", i.e. have degrees from prestigious colleges. Of course that still doesn't guarantee they will have the necessary skills from the get-go, but if things don't work out the hiring manager can at least cover his/her own ass by saying, "well, he/she was a <prestigious college> graduate..."