Speaking to reporters at CES in Las Vegas this week, Hirai claimed that it can take 5-10 years before he can truly judge if a product has been successful or not.
“Long term is what is important,” he said, according to The Wall Street Journal.
He pointed out that similar questions were asked about PS3 adoption early in its lifecycle, and that he now judges the home console to have been successful.
You don’t have to be an analyst to see that Vita is in a tough spot. Having launched in Japan in December 2011 and in North America and Europe in February 2012, worldwide Vita sales stood at 1.8 million units at the end of Sony's financial year which concluded March 31, 2012.
In the first quarter of the current business year ending March 31, 2013 Vita sold a further 400,000 units globally, less than half as many as the ageing PSP managed in the same three month period.
Since then, Sony has grouped together Vita and PSP sales in its quarterly financial results in what’s perceived in some circles to be a strategic move designed to circumvent public disclosure.
In November 2012 the company forecast a combined total of 10 million Vita and PSP sales during the current financial year, a figure downwardly revised from 16 million units just six months earlier.
Hirai has also reacted to this week’s announcement of Nvidia's Android-powered portable console, which is currently titled Project Shield.
"I wasn't as surprised as you might think," the former Sony Computer Entertainment president said, as reported by International Data Group. "If you look back through the pages of history, there have been other attempts [to enter the handheld gaming market].
"It's difficult to break into. I've managed this industry, so I know."
Pressed on whether it was a good time to attempt to enter the sector, Hirai added: "It's too early to tell."