Allow me to call a timeout in the Raiders’ Stadium Follies for this note of reality:

The Raiders are not getting a new stadium. They are not getting it in Oakland, Las Vegas, San Antonio, Mexico City or Irwindale.

The Raiders are master builders in one respect: They have built more imaginary stadiums than any team in existence, barely edging out the A’s.

The Raiders’ three most realistic options: Rent Levi’s Stadium, move to Los Angeles and rent the Rams’ new stadium, or keep playing at Roto-Rooter Field.

Read my lips: No new stadium.

There is a big picture and a small picture. The big picture is that this is a horrible time to finance and build a football palace. The small picture is that every stadium deal the Raiders have considered is like San Francisco’s Millennium Tower. It looks glorious from afar, but on closer inspection, it is sinking and leaning.

Big picture: The NFL is in a slump.

TV ratings are down roughly 10 percent since last year, although a Guggenheim Securities analyst says that the NFL “remains the most powerful franchise on TV.”

Commissioner Roger Goodell calls the TV dip “cyclical.” What’s he going to say? Man the lifeboats?

There is growing evidence that the NFL has squeezed the turnip nearly dry. The turnip in this case is you, the fan. The league can’t keep jacking up ticket prices, stuffing more commercials into every telecast, and watering down the product, without approaching a saturation level.

The league has concussion issues and other pesky, won’t-go-away problems.

If the Raiders get close to a stadium deal, banks will get involved. Hard-eyed money people will be asked to lay their cash on the line. They will be skeptical of any deal that depends on the NFL continuing to wallow in boomtown riches. That’s so 2010.

If you build a stadium, and revenue from tickets, licenses and league growth falls short of optimistic projections, the deal teeters. Same if the team falters.

The new reality can be seen in action at Levi’s, where the stadium is half-empty and the fans are fully pithed-off. Investors, beware.

Now to Raiders-specific details:

The Ronnie Lott group envisions a $1.3 billion stadium. That figure ignores almost-inevitable cost increases and overruns. That $1.3 billion, in the real world, becomes closer to $1.5 billion.

Oakland will kick in $200 million, and will give away (more or less) land worth about $150 million. That’s a tidy investment for a city whose residents don’t all wear scary costumes and live in the Black Hole.

Remember, the city is still on the hook for an estimated $91 million from the last sweet deal its political geniuses swung with the Raiders in 1995.

After the city kicks in its share, the tab is at least $1.3 billion. The league will ante $300 million. The Raiders will contribute $200 million, much of it (hopefully) from the sale of seat licenses, which were vital to the Levi’s project and might be a dying concept.

That leaves Lott & Pals with a bill for about $800 million. Then they would need a ton more money to build their village of restaurants, hotels and housing.

Lott’s folks probably would expect a thank you in the form of a solid chunk of team ownership. Might as well ask Mark Davis to get a Mohawk.

So the Oakland deal is not as slam-dunky-no-brainy as opening up a Dunkin’ Donuts.

What about the Vegas deal?

That one requires $650 million from casino mogul Sheldon Adelson. Some believe he wants about one-third ownership of the Raiders, a team valued at just more than $2 billion, although Adelson denies that. If Adelson does want a stake, Davis would rather wear cornrows.

The league would have to approve the move to Vegas. The other team owners might be leery of bedding down with Adelson, and might be cool to abandoning the vibrant Bay Area in favor of the desert. Owners might fear an image disaster, the Raiders baking in their half-empty new stadium, reinforcing reports of an NFL death spiral.

The Vegas deal is based on projected heavy attendance by visiting-team fans coming to town to par-tay. Imagine the Black Hole liberally sprinkled with visiting-team colors. Bye-bye to the Raiders’ precious home-field advantage.

None of the breakdowns I’ve seen of the Vegas deal factor in the $500 mil (or so) relocation fee the league will assess. One more thing: Seriously, I hear that Davis’ mother, the co-owner of the team, is opposed to Vegas.

If the Vegas and Lott deals don’t work, the Raiders’ only option is to become a tenant, in Los Angeles or at Levi’s.

The Chargers have first crack at moving to L.A. If they pass, would Davis opt in?

Davis has zero commitment to Oakland, but is SoCal really that attractive? Fans supported the L.A. Raiders back in the day, but there was a massive shrug when the team moved back to Oakland. It’s an “entertain us” town, and what happens if the Raiders don’t go deep in the playoffs every season?

If Davis is grudgingly willing to share a stadium, why not the one in Santa Clara? Davis could keep his share of the Raiders’ ownership, and be $200 mil richer for not building a stadium.

This whole drama could drag on for years. In the meantime, take it from a financial genius who doesn’t even know how to spell morgaige: If you’re dropping $5 into the Raiders’ stadium office pool, go with Irwindale. Deep pits, deep pockets.

Scott Ostler is a San Francisco Chronicle columnist. Email: sostler@sfchronicle.com Twitter: @scottostler