Relevancy based on record sales.
There seems to be a recurring argument that anyone who like the Beatles would already own all the records, and people have been saying that everytime this rumor pops up.
But the numbers do not agree. In 2008, the year before the remastered albums came out, when most people who knew anything about the Beatles were least likely to buy, the Beatles still sold 1,339,000 Albums.
The year before, a more typical year as the remasters had not yet been announced, the Beatles sold 1,994,000 Albums. .
In 2000, when 1 was released, which was nothing more than basically a "greatest hits" record, giving the public nothing they hadn't already heard, they sold 7,289,000 Albums.
And while the 2000 sales were high, about 2million records is consistent, year after year. People just keep buying them, whether they are 13 year olds just introduced to them, or college kids just introduced, or Xer's who never quote got around to buying all of them when they were younger. Or they may be Boomers who have bought them on vinyl, and the 86 release CD, and have been meaning to buy the remasters, but, because they are busy, haven't gotten a chance. And, if they allow single track sales, their will be quite a few sales for those who do not want to buy an album, they just want Twist and Shout, or She Loves You or Penny Lane.
It probably doesn't make sense to quite a few of us who know every torrent site, and who, if they were to get into a band, would buy it's entire catologue in a short amount of time, but that is not representative of the average consumer, and the sales statistics bare this out.
ADDED, The above info comes from Nielsen Soundscan, and only includes North American Sales.