This. I did an MBA and learned more in one year of physics (my undergrad) than I did in the ~2 years of my MBA. I did get a very large boost to my salary (changed fields) and future employment prospects, but it was mostly due to the contacts and network I made.
I respect my engineering degree more than I will ever respect my MBA should I get it, but if you can't beat them, you should join them IMO.
I paid for it myself, and it was definitely worth it. I had no promotion promise, switched fields, and went into debt for the entire amount, but I would easily make the same choice again.
I've got 4 friends who went for their MBAs. It helped none of them, but at least two of them got the whole thing paid for by their employers. The other two went into significant debt that will take years to repay.
99.9% of companies don't have the internal capabilities to train people to MBA level. They either hire MBAs, or pay to send their top talent to do an MBA.
You don't need an MBA to be a successful manager. That's my point.
If my choices are to pay for an average employee to do an MBA with a salary bump when they come back, or take my chances hiring someone who got their own MBA, which do you think I'm going to take?
Except the problem is that great employees are passed over time and time again. Additionally, tuitition reimbursement is capped at the IRS limit ($5250) so even if they say "Go back for an MBA and we'll pay," that won't cover much.
Remember, my goal here is to get a decent MBA at a bargain price. If I wanted to go into debt and get a great MBA, I can literally walk across the street (I can actually see the business school out of my office window) to Indiana's Indianapolis campus and enroll. That's a $55K+ program, however.