Why do blockbusters rarely win top honors at Oscars?

That's because -- let's face it -- most of the films shortlisted for Academy Awards glory are relatively small-budget independent flicks, not crowd-pleasing blockbusters.

And it's even more the case this year, with only one of the eight films up for best picture produced by a major Hollywood studio.

Take the two frontrunners: "Birdman" was written, produced and directed by Mexican Alejandro Gonzalez Inarritu for some $18 million, while "Boyhood" cost only $4 million to make -- over 12 years.

That is a drop in the ocean compared to the $100-200 million budgets of studio hits from last year like "Hunger Games: Mockingjay - Part 1," "Guardians of the Galaxy" or "Big Hero 6."

Each of them made at least $200 million at the North American box office alone.

By comparison, "Boyhood" and "Birdman" have so far earned $44 million and $72 million, respectively, in worldwide ticket sales.

Other best picture Oscar nominees like "Whiplash" and "Selma" made even less.

"The Theory of Everything" -- the story of British scientist Stephen Hawking -- did better ($98 million) and "The Grand Budapest Hotel" made $174 million, but that's still a long way from the year's biggest blockbusters.

"A lot of times, 'Oscar bait' movies are very personal projects that have meaty roles for actresses and actors, but don't necessarily reach a wide audience," said Jeff Bock of box office tracker Exhibitor Relations.

Changing Oscar trends

A decade ago, Hollywood blockbusters were more regularly rewarded by the Academy: "The Lord of the Rings: The Return of the King" won the best picture Oscar in 2004, after "Gladiator" in 2001 and "Titanic" in 1998.

More recently, voting members of the Academy of Motion Picture Arts and Sciences, which hands out the golden statuettes, have honored indie darlings such as "No Country for Old Men" (2008), "Slumdog Millionaire" (2009) and "The King's Speech" in 2011.

This year, the exception is Clint Eastwood's "American Sniper."

It's the only studio film -- produced by Warner Bros -- in the best picture race and is nominated in five other categories.

The movie, based on the life of Navy SEAL sniper Chris Kyle, has been a huge box office hit, making $400 million since its December 25 release, with $300 million in the United States and Canada alone.

Its $60 million budget puts it somewhere between an independent and a big studio movie in terms of cost.

As Hollywood's finest gather for the Oscars on Sunday, US film-going audiences have made their tastes known.

Erotic romance "Fifty Shades of Grey" is far and away this month's box office smash hit, amassing more than $300 million worldwide since its opening about a week ago, despite decidedly lukewarm reviews.

In Oscars history, the biggest-budget film ever nominated was James Cameron's sci-fi blockbuster "Avatar," which made $2.8 billion at the global box office.

But it was beaten at the 2010 Academy Awards by "The Hurt Locker," about a bomb squad maverick in Iraq, which only made $49 million worldwide.

Other recent winners including "Crash" (2006), "The Artist" (2012) and even last year's "12 Years a Slave" -- all low-budget indies with modest domestic box office hauls.

Ethan Hawke, nominated for best supporting actor for his work on "Boyhood," said there is a crucial link between independent movies and awards season.

"Awards are the industry's way of advertising itself. If we didn't have awards, then producers would have no agenda. The only agenda would be to make money and awards create a counter-agenda of something substantive," Hawke said.