Why was Led Zeppelin's first album mostly just covers or heavily inspired from other artists?
Yes. I Can't Quit You Baby, and You Shook Me were pretty much straight covers. Dazed and Confused, while having different lyrics, is clearly the same song written by Jake Holmes, a song that Page also performed while with the Yardbirds. Babe I'm Gonna Leave You is pretty much a cover. Your Time is Gonna Come, and Good Times Bad Times may be the only two songs on the album that could be called original. For the conspiracy minded, this might explain why the band chose to record the album without record company backing. Page paid out of pocket for all their studio time. No record company oversight.
That's quite common for a new band. It takes time to build up a repertoire of original compositions, and to be a band, you have to play together as one. Covers are a staple for any new act. The Beatles did mostly covers during their Cavern Club and Hamburg days. Six of the fourteen tracks on their first album were covers. The Rolling Stones' first release contained only one original song.
No. They are just a Greta Van Fleet ripoff.
Simon and Garfunkel, hands down - no comparison
Because it was.
Led Zeppelin were honing their R&B skills and testing the public and critical reception of their album.
Zeppelin's earliest work was famously very derivative. Their MO early on was basically perfecting an already existing craft, where Sabbath and Purple were more about starting new crafts altogether. But as LZ moved forward and found their sound they wrote more unique and influential material.
As was The Beatles, as was The Rolling Stones
To this day I still don't see the significant similarities to "Nervous Shakedown". The band's original ideas came through even on the numbers mentioned through their transformations of the songs. "Dazed and Confused" and "How Many More Times" have instrumental passages that deviate wildly from the original songs. The former, in particular, turns a moody folk song into a descent through Hell.
Wow. If it wasn't for your enlightening insights, the world would be in the dark. Why don't you run for president of the US?
The Lord Humungus.
You have a band of professionals forming a new band. So the usual practice is to start playing things you all already now and have played previously, to build some common ground.