The Elzabethan playhouses were like Hollywood studios in the golden age; they were entertainment factories, turning out plays on a production line.
There were lots of writers servicing the Elizabethan stage. Lots of competition. Lots of friendly (and not so friendly) rivalry.
Theatre was a collaborative art (just like the movies.) A good number of the plays in the Shakespeare canon were collaborative works. Many were rewrites (remakes) of earlier hits.
Our text of Macbeth is almost certainly not Shakespeare's orginal but a (respectful) rewrite by Thomas Middleton.
Shakespeare wasn't writing at leisure; he was feeding a machine. If some of the plays feel as if they were thrown together it's because they were.
I'm not sure how many plays the Kings Men got through in a year, but it was a prodigious number. There was only a small audience (consider the size of Elizabethan London) and it had to be wooed back by new product. Plays only ran for a handful of performances. It was like the turnover of movies in a neighbourhood movie house (before the advent of the blockbuster.)
I'm in awe of those actors- having to memorise those huge texts at the rate of about one a week. How on earth did they do it?
That's one of the reasons why Shakespeare wrote in verse. Verse with a regular beat is easier to memorize than prose.
And Shakespeare wasn't only writing the stuff; he was acting and producing and helping run the playhouse. No wonder he retired in his 40s.
Like many of the greatest artists he was also a hack. He served the system. He worked under pressure. He was subject to market forces.
The 20th century artist he most resembles is Howard Hawks: able to turn his hand to anything- to any genre- and make a good fist of it.