This is how the car-rental process goes for most travelers: They find the cheapest price, select a "category" or "class" of vehicle that rarely correlates with any automotive verbiage they understand, make the reservation, and hardly think twice about the brand name of the rental firm.

And this is how the car-rental process goes for most business travelers: They find out if their company has a corporate rate from some rental firm, learn the car size they are allowed to choose, then make the booking.

Sorry if that sounds cold-blooded and generic, but such has always been the way of car rentals. Fleets are stocked with the same cars from the same carmakers. With rare exceptions, you can't even reserve the make or model you want to drive. No frequent-renter program rises to the level of airline frequent-flyer or hotel frequent-guest plans. Branded service programs, like Avis Preferred or Thrifty Blue Chip, are designed to minimize your interaction with the company at the point of sale. Even breakthrough "loyalty" programs like Hertz #1 Gold or National Emerald Aisle are little more than clever twists on getting you to your car faster.

In fact, about the only time you hear travelers talk about car rentals is when the price is "too high." Of course, at less than $40 a day on average, according to CarRentalExpress.com, which claims they can get it for you cheaper, renting a car worth $15,000 to $50,000 may still be cheaper than renting a $900 carpet-shampoo machine from your local supermarket. There are also occasional gripes about misleading ups and extras since the rental companies offset low base price with a bewildering series of charges like "concession recovery fees" (that's their way of shifting the cost of airport real estate to you) or wildly inflated insurance levies (at $25 a day for the "collision damage waiver," you pay an annualized premium of more than $9,000).

Except for price, Jerry Seinfeld's spot-on screed about "taking" and "holding" reservations, and some hoary advertising slogans ("Let Hertz put you in the driver's seat" or "Avis tries harder"), the car-rental business is remarkably drab, something that hasn't escaped the notice of the people who work in the industry.

"I hate this business," one senior-level executive of a car-rental firm told me years ago. "There's no loyalty, high fixed costs, low margins, and the customers are never happy."

He's in the hotel business now and laughed when I told him I'd be writing about Hertz Global Holdings' proposed $1.27 billion purchase of the Dollar Thrifty Automotive Group. If approved by federal antitrust regulators, and if it survives a possible counteroffer from the Avis Budget Group, the Hertz-Dollar Thrifty deal will concentrate about 95 percent of the nation's rental business in the hands of three companies. That brings the industry full circle, back to the early 1980s, when I first started renting cars for business trips.

Back then, the industry was dominated by Hertz, perennial No. 2 Avis, and National Car Rental. The industry expanded rapidly in the 1990s when the major firms were all owned by car manufacturers. The carmakers used their rental arms to keep manufacturing levels artificially high. That meant insanely low daily prices for us, and cars that rarely hit the 10,000-mile mark before they were banished from the rental pool and sent off to used-car lots. But the rapid decompression of auto manufacturing in the last decade led carmakers to offload the rental firms, several of which eventually went bankrupt and all of which have had trouble raising cash to fund new fleets. A full-size 2008 sedan I rented over the Christmas holidays had 41,000 miles on the odometer, higher mileage than I've run up on my own 7-year-old convertible.

The industry's consolidation in recent years has left Enterprise Holdings, a privately held entity formed in 2009, in control of the Enterprise Rent-A-Car, National, and Alamo Rent A Car. After bouncing from General Motors to RCA to United Airlines and finally to Ford, 92-year-old Hertz Corporation was sold to private investors in 2005. They took it public in 2006, and, early last year, Hertz Global Holdings purchased bankrupt Advantage Rent-A-Car, the creation of flamboyant Denny Hecker, the Minnesota car dealer whose empire crumbled in a mountain of debt.