Competition could make it difficult for Spotify to achieve the sort of profitable scale necessary to go public here in the United States, Fool contributor Tim Beyers says in the following video.

That isn't to say the business is a failure. Far from it: Spotify's user base grew to 20 million last year from 11 million the year prior. More current estimates peg Spotify's total user base at 24 million across 32 countries, with 6 million paying for the service. Count Technology Crossover Ventures among the private investors in love with the story: The firm earlier this month led a $250 million fresh round of funding at a $4 billion valuation.

So what's the problem? Growth isn't coming at the pace U.S. IPO investors would expect, Tim argues. The Independent newspaper reports that U.K. revenue fell 4% last year, thanks in part to an accounting change. Total revenue came in at about $585 million.

By contrast, U.S. rivals Pandora Media (NYSE:P) and Sirius XM Radio (NASDAQ:SIRI) grew revenue 55.7% and 12.9%, respectively, over the same period. They also serve more listeners: Sirius has more than 25 million paying subscribers while Pandora now has more than 70 million active users. Adding Google's "All-Access" Music service, now available on iOS devices, to the mix won't help.

For its part, Spotify told The Independent that its "key priority" for 2013 is user growth, which means profits are likely to remain elusive as the company battles to emerge from a field of tough (and proven) combatants, Tim says. A U.S. public offering can wait.

Do you agree? What would you want to see before investing in a Spotify IPO? Please watch the video to get Tim's full take and then leave a comment to let us know where you stand.