Short answers, pulled from the story.
Rock Band was developed by Harmonix and first released in 2007. Harmonix, a company born out of MIT's Media Lab, built the game after being acquired by MTV Games, a Viacom subsidiary, for $175 million in 2006.
As of January 2024, Rock Band 4 supported over 3,000 songs. The catalog was built through weekly downloadable content releases and the ability to import songs from previous Rock Band games.
The Rock Band Network, a service allowing artists and labels to publish their own songs for the game, was fully shuttered in September 2014. At its peak, it offered over 4,000 tracks from 1,200 artists. All Rock Band Network content was delisted from Xbox 360 and PlayStation 3 in February 2018.
Harmonix was acquired by Epic Games in November 2021. Prior to that, Harmonix was sold at the end of 2010 to Harmonix-SBE Holdings LLC, an affiliate of investment firm Columbus Nova, after Viacom divested the company.
The Beatles: Rock Band is a standalone game released on the 9th of September 2009, developed by Harmonix under an exclusive agreement with Apple Corps, Ltd. It covers United Kingdom-released songs from Please Please Me through Let It Be and includes downloadable albums Abbey Road, Sgt. Pepper's Lonely Hearts Club Band, and Rubber Soul. Due to its licensing terms, no content from the game can be exported to other Rock Band titles.
On the 5th of October 2025, Harmonix announced Rock Band 4 would be delisted because many of its music licenses were expiring after ten years. Players who had already purchased the game retain the ability to download and play it, and downloadable content also remains available for existing owners as individual licenses expire.