The last Dodge Ram pickup rolled off the assembly line at the Fenton North Plant on Thursday. The South Plant, which assembled minivans, shut down in October. The two plants, which once employed as many as 7,500 workers, soon will be mothballed.

“It’s almost as though there’s been a death in the family,” said Fenton Mayor Dennis J. Hancock of losing an iconic employer and the enterprise that put the city on the map 50 years ago. “Driving by and seeing the empty parking lots — it’s a blow.”

But don’t feel too sorry for the city of Fenton. Mr. Hancock argues that his city of 3,400 people will carry on. Indeed, in terms of its ability to provide essential services, he’s confident Fenton can absorb the loss in stride.

Fenton’s experience offers lessons for local governments throughout the St. Louis region, and the most important lesson is this: Necessity is the mother of invention. For cash-strapped municipalities, necessity should give birth to real regional cooperation. It’s the only way out.

Fenton had hoped for the best, but the mayor said the city has been planning for a Chrysler Plant closing for nearly a decade. Chrysler directly contributed about $500,000 year in tax revenue to Fenton, so the city had to prepare for the worst.

Perhaps the smartest move Fenton made came in 1995: It abolished its police department and contracted with the St. Louis County Police Department for patrol and other public safety services. That move gave the city a little financial breathing room.

Mr. Hancock estimates that move has saved the city $1 million per year — about twice the revenue lost from the Chrysler closing. The city also contracts with the county for building inspections, saving another $75,000 per year.

How many municipalities in this region can afford to ignore such savings, even in better times?

Fenton has advantages that enable it to cope with the loss of a major employer. For one thing, the city once had a large concentration of Chrysler workers, but no longer. It has become more a white-collar community with no dominant employer; the loss of the Chrysler jobs had a less direct impact on the city.

What’s more, the city is a shopping hub that serves not just the immediate and adjacent communities but reaches into Jefferson County, generating considerable sales tax receipts. Fenton played the TIF game early and well, subsidizing the Gravois Bluffs shopping area, becoming big-box central for a large swath of the region.

Modern municipal finance in the St. Louis region hasn’t been about growth in well-paying jobs. It’s been an arms race for sales tax receipts. Cities place big bets by subsidizing retail developments in hopes of capturing consumers from neighboring communities. That means retail growth in St. Charles County puts a crimp on sales tax collections in the Chesterfield Valley.

Someday, Jefferson County will try to put the arm on Fenton, luring sales tax receipts to its side of the county line with big boxes and megacenters.

There’s a better way to do things, but it involves moving away from TIFs for retail centers and investing in a regional strategy for economic growth. Fenton dodged the Chrysler plant closing, but it shares the region’s destiny. We can build together or we can bleed one another. That’s the choice.