Ron Howard describes himself as "not a very good businessman".

This seems an unlikely self-assessment from the man who rose from playing Richie Cunningham in Happy Days to the force behind the Oscar-winning A ­Beautiful Mind (for which he was named best director), Apollo 13 and Frost/Nixon, as well as The Da Vinci Code and its sequel Angels & Demons.

However, the director, now 59, is absolutely serious as he reflects on the changes affecting the industry, where blockbusters are based on comic books, and movies like Rush, his latest, are rejected by the studios and have to take another route to the big screen.

"There's no question that when DVDs, which were providing studios with a reliable profit margin, began to shrink and weren't replaced by downloads, the executives looked around and said, 'What should we be investing in and what can we market?' And they've become more and more conservative."

"I think all it does is help define who loves their work enough make the kinds of sacrifices to keep doing what they're doing. If I was really trying to maximise my earning power I would settle in on a brand, but I enjoy the creative adventure of exploring lots of different stories with different tones and styles."

While some may view Rush as a racing film, Howard sees it as much more.

"I felt like it was a survival story and a story of evolution," he explains. "Both guys have an idea of what it is they want to be and they have a burning need beyond the obvious glare of the spotlight. Like a lot of young men they're not thinking too much about what the price will be. They push each other and, as they climb the ladder, the air gets thinner and the stakes grow higher and higher. It changes them and they start to pay a price for it.

"It's the kind of thing that young men can never quite appreciate. So, it's a kind of a rites of passage story in a way too."

Howard also thinks sport and the men and women who compete in it are "the first and still most reliable and relevant [form of] reality show". Hunt was a renowned playboy, while Lauda was and continues to be fiercely pragmatic and someone who doesn't suffer fools politely.

"The thing to be celebrated about Rush more than anything else is that these guys both exhibited rigorous honesty, and they lived by that," Howard continues. "Neither denied who they were, there was zero hypocrisy, they were very different, but they were their own mavericks.

"There was no Yoda guiding them to some higher plain of enlightenment - they didn't listen to anybody and they did it their way. But they didn't pretend to be anything different. And I think it's why both men were respected and is what, ultimately, brings the nobility to the way they chose to compete and live their lives."

Howard's respect for both men is similar to that which he held for another of his former subjects, the legendary broadcaster Sir David Frost, whose death on Saturday from a heart attack was announced just hours before the director spoke to me.

Clearly saddened by the news, Howard was also keen to pay his own tribute: "I really enjoyed getting to know Sir David. He was bright and witty and I really admired and respected his entrepreneurial side.

"He was a great personality - fast and funny and smart - but he had a kind of an audacity, or a courage, that I really admired, both in terms of the way he tackled his work but also with what he thought about. He was a pioneer as a producer."