The bad news just keeps coming for 49ers fans. First they lost quirky but effective coach Jim Harbaugh, then they watched the team crash and burn in a 5-11 2015 season.

And now their loyalty is starting to cost them money.

When glittering Levi’s Stadium opened in Santa Clara in 2014, there was a land rush for season tickets. The 68,500-seat facility sold out months before the first game, with fans lining up to not only pay for season tickets — which cost $375 to $3,750 a seat — but a one-time “stadium building license” that sold for $2,000 to $80,000.

That sounded steep, but as fans said, “No worries.” It wasn’t a ticket purchase, it was an investment. Some said they planned to pick a few games to attend and then would sell the remaining tickets on a hot resale market to cover the price of the SBL. And, the 49ers told them, the SBL might even go up in value.

Or not.

General exasperation with the team has the market for both tickets and SBLs plummeting. The idea that SBL owners would be able to sell their license quickly, and perhaps at a profit, has turned out to be a fairy tale.

Browsing the “marketplace” for SBLs, which can be accessed on the Levi’s Stadium site, is discouraging for potential sellers. On Friday there were 1,825 licenses for sale, representing 4,601 seats. Not only is that an increase of nearly 800 from last spring, but also a quick scan of the seven-page list finds dozens of licenses priced below market rate.

Another site totals the number of SBLs sold in the past year: 382. After all, why buy an SBL and a season ticket when single-game seats are available at cut-rate prices from ticket brokers?

Although the 49ers tout the advantages of an SBL — priority access to other events at Levi’s like concerts and world-class soccer games — there’s a big caveat: If you don’t sign up for a season, you’re out of luck for good.

A 49ers spokesman, who would only speak off the record, forwarded a copy of the contract fans signed when they bought a license and season tickets. It says if the license holder does not purchase season tickets by the ticket deadline, he loses the chance to buy this year “and all NFL seasons to follow.”

“They’re in a bind,” said Santa Clara Vice Mayor Teresa O’Neill, who is a member of the city’s Santa Clara Stadium Authority. “If they don’t pay for tickets, they forfeit.”

But, of course, they still owe payment for the SBL. Many fans got around the high SBL fee by arranging financing over as many as 10 years. Just two years into the deal, some are considering stopping payments and walking away.

“We have asked how many people have defaulted on their licenses,” O’Neill said. “They are saying it is minuscule and that licenses are reselling.”

But that’s not what we see on the marketplace, which makes the default option more worrisome for the team and the Stadium Authority. If large numbers of license holders stop making payments, what do the 49ers do? Go after everyone in court?

Because that creaking sound you hear is the Levi’s Stadium business model tipping sideways. The seat licenses are the cornerstone of the $950 million the Stadium Authority put into construction costs.

In March last year, the Stadium Authority said in its budget report that more than $31 million in SBL proceeds has yet to be collected. Granted, it isn’t $900 million, but that’s still a tidy sum. And they are counting on fans to pay it off in their license fees.

The 49ers just announced that “there are a limited number of season tickets and stadium builder licenses available.” They’ve also sent an offer to season-ticket holders, asking if they’d like to upgrade to better seats.

Remember, not only was the stadium completely sold out before the 2014 season, there was a waiting list of people who wanted to buy SBLs and season tickets. Now the team has reopened the market. The problem is the licenses have become a money loser and single tickets are dirt cheap.

All of which creates another unintended consequence. With cheap individual seats available for almost every game, the stadium is more likely than ever to be filled with one-time fans, who tend to treat a game like a bachelor party. Instead of building a sense of community with fellow season-ticket holders who sit in the same section for every game, you may end up next to some obnoxious jerks — and paying thousands of dollars for the experience.

What to do? O’Neill says she has the answer. She won’t miss a game.

“I bought a big, high-def TV,” she said.

C.W. Nevius is a San Francisco Chronicle columnist. His columns appear Tuesday, Thursday and Saturday. Email: cwnevius@sfchronicle.com Twitter: @cwnevius