Another music streaming service bites the dust.

The assets of Rdio — a subscription streaming music service that competed with the likes of Spotify and Apple Music — were acquired by Pandora for $75 million in cash.

This isn't a happy ending for Rdio. In fact, the $75 million transaction is "contingent upon Rdio seeking protection." Rdio will wind down the Rdio-branded service in all markets.

Whatever Pandora decides to do with the Rdio assets — Rdio as a brand and as a standalone service is dead.

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Created by the two guys who founded Skype and Kazaa, Rdio had a lot going for it in its early days. It had a web, desktop and mobile option, was attractive and had a big library.

But it also faced a giant elephant in the room: Spotify. When Spotify launched in the United States in the summer of 2011, there were already a number of on-demand streaming companies. The biggest of those companies were Rhapsody, MOG and Rdio.

MOG fell first. It was acquired by Beats in 2012 and some of its technology was used as the basis for Beats Music (and Beats Music is the basis for Apple Music). Rhapsody still exist — somehow — but despite being the pioneer in on-demand subscription streaming, it hasn't made much traction.

In the ensuing years, the competition has become even harder fro Rdio. Not only with other subscription services (Deezer, Tidal, Apple Music, Google Play Music all launched post 2011), but with the undisputed king of subscription streaming: Spotify. And that's without even addressing YouTube.

If we're being honest, Rdio has been on life support since July 2011, when Spotify first came to the United States.

Competing with free

One of Spotify's core differentiating features is that anyone can listen to music on-demand for free — on the desktop. If you want to skip ads and listen on-demand on mobile, it'll cost you — but the free desktop plan has helped the service gain tens of millions of users.

Rdio, like every other on-demand service in 2011, didn't have a free option that was as robust as Spotify. The company tried various methods of giving users access to playlists, curated radio and select on-demand streaming on the desktop in the ensuing years (and even overhauled its free plans last year), but it could still never really compete.

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Even Apple, the largest company in the world, isn't immune to the struggles of competing with free. It helps that Apple entered the space in 2015 — when people are increasingly listening to music on phones and not desktops (Spotify's free mobile offering is better than a lot of other services, but it's still basically Pandora. If you want to hear music on-demand on you phone, you're going to be paying $10 a month, whether it's from Apple, Spotify or Google).

If Rdio ever had a chance at competing with Spotify — which despite launching in the U.S. later, had more money and was already a popular brand in more countries — it was four years ago.

Fighting against a well-capitalized giant is tough. It's even harder when that giant has a core product that is every bit as good as your own.

This isn't to say Rdio was a bad service. The company employed some great UI and UX designers. Back in 2011, I called the Rdio for Mac app "iTunes for the Cloud" — a feat the real iTunes wouldn't fully achieve until 2015.

When good isn't good enough

Rdio's ending shouldn't be a surprise to anyone watching the company. The company has shed executives en masse in the last year. The attempts at reinvention have largely failed. And the competition is no longer just Spotify, but Apple and Google.

It's a shame that Rdio is going to die. It was a genuinely good service.

For its part, Pandora doesn't even seem to be interested in creating an Rdio component to its streaming radio service. The company wasn't explicit about its full plans for the Rdio assets and team members on a call with investors, but it seemed clear that the point of this acquisition was not to try to compete with Spotify and Apple Music on traditional turns.

Instead, this is about making Pandora's product better. Until the next, more popular streaming service comes along.