for those that can't open the link
Lennon’s on sale again” could be understood more straight-forwardly.
I explain:
First things first, simple chronology: David Bowie’s “Life on Mars?” was released in December 1971. Three months earlier, in September 1971, John Lennon released his 2nd solo album (and probably the most famous one): “Imagine”; we can figure that at the time David Bowie wrote “Life On Mars?”, the promo around Lennon’s release of “Imagine” was all happening, hence the “on sale again”. Lennon was literally going to sell/selling a new album again. Bowie probably witnessed the whole promo directly and daily.
However, “Working Class Hero”, Lennon’s timeless Working class anthem, was actually released a year earlier, in December 1970, on Lennon’s 1st solo album (“John Lennon/Plastic Ono Band”). We can, of course, draw a few parallels between Soviet Communism imagery and the themes Lennon explores in the song (working class, struggle of the classes, condemnation of religion, etc.). And there’s also this funny pun by Bowie with the similarity of pronunciation between Lenin (Vladimir Ilyich Ulyanov, former leader of the Soviet Union and Russian Communist party + inventor of Leninism, first of his name), and Lennon (John, the singer, musician, songwriter, activist, and also ex-Beatles).
The song, giving a poignant rendition and definition of what it’s like to grow up in the working class and what it’s like to belong to it (and why we should all be a “working-class hero”), put the focus on all the working-class people. Although Lennon beautifully pays tribute to all the working class people with his song, that doesn’t mean all these people became famous after Lennon’s song was released. And Lennon actually seems to self-proclaim himself as the “working class hero”.
So with “Now the workers have struck for fame, Because Lennon’s on sale again”, Bowie simply says that now Lennon released his new album, the workers (that is, the working class) feel the rightful need to strike for fame, to claim their right to become famous. At least, as famous as the self-proclaimed Working Class Hero: John Lennon.
There lies an interesting paradox since Lennon was defending with pride the working class with “Working Class Hero”, but the workers themselves could have possibly perceived it as a sign of arrogance and nonsense from someone who became really wealthy (he was a former Beatles’ member after all, no need to say he had nothing to complain about financially speaking). Probably that John Lennon couldn’t really be a working class spokesperson to them, since he had never been part of it (even in the Liverpool days, he was raised by his aunt who was part of the middle-class).
Bowie gives throughout “Life on Mars?” a rather sad and pessimistic statement on the current state of the society/World of his time, which is why “the workers” may appear greedy “for fame” and ready to denounce Lennon, whom they may consider as being an usurper and a fraud (selling discs and becoming rich at their expense).
To a larger extent, yet quite cleverly, Bowie (with “Lennon’s on sale AGAIN”) could also nostalgically refer to The Beatles’ 4th album called “Beatles for Sale”.