Robocop was their "Plan B". "Plan A" was ED-209. As explained by Johnson (in the script):
When ED209 ran into serious delays the old man ordered a backup plan. Probably to light a fire under Jones' ass. Old Bob here gets the assignment. Nobody in Security Concepts takes it seriously.
Note that part at the end which agrees with your question - initially the Robocop program was not taken seriously.
However, when the ED-209 spectacularly failed during a boardroom meeting, Bob Morton took the initiative:
Old Man: Dick, I'm very disappointed.
Dick Jones: I'm sure it's only a glitch, a temporary setback.
Old Man: You call this a glitch? We're scheduled to begin construction in six months. This "temporary setback" could cost us millions in interest costs alone.
Bob Morton: Not necessarily, sir. You may be aware of the Robocop program designed by myself at Security Concepts as a contingency against just this sort of thing.
Dick Jones: Thank you for your concern. This is something we could...
Old Man: Wait a minute. Dick! Maybe what we need here is a fresh perspective. Tell me about your plan. How long will it take?
Bob Jones: We've restructured the police department and placed prime candidates according to risk factor. I'm confident we can go to prototype within 90 days.
Old Man: Very good. Get your staff together. I'll expect a full presentation in my office in 20 minutes.
Bob Morton: Thank you, sir.
Nevertheless, after only one month on the streets, Bob Morton predicted:
Here at Security Concepts, we're predicting the end of crime in Old Detroit within 40 days. There's a new guy in town. His name's RoboCop.
So, even though he couldn't be mass produced, that wasn't necessary. On his own, Robocop dramatically reduced crime, not least by killing the crime lord Clarence Boddicker and drug baron Sal and shutting down their respective operations.
This also matches one of the themes of the film - American corporations' big, mass-produced machines (the ED-209 and 6000 SUX) versus the underdogs, most notably Alex Murphy / Robocop.
The script link has some errors. I've tried to patch it from memory but there might be a few words wrong.