Blake's Main Chance:
Becoming an Individual:
Blake was born an individual, a very distinctive human being-- until he got married in his early twenties.
That carried responsibilities; as a bread-winner he of necessity more or less 'joined the crowd'. But he remained a misfit (we all know such people; you may be one), call them unwilling joiners. Everyone must have sustenance of some kind: emotional or financial, usually both.
The crowd is made up of the kind of people who watch the ads to see what people are doing so they know what to do, so they can do the same thing.
People in the crowd generally want to 'get ahead' (whatever that may mean); it takes the place of 'following your bliss'; instead you try to follow the 'bliss' of the person in the crowd whom you most admire, your role model, your 'father', so to speak.
(Jesus had something to say about your 'father'):
"call no man father upon the earth: for one is your Father, which is in heaven". (Matthew 23:9)
In particular Blake wanted to be able to 'hold his head up'--financially and intellectually. He lent his enormous artistic gift in the service of other people; he especially admired the famous artist, Sir Joshua Reynolds--until he saw the artistic chasm that loomed between the two. He joined the 'Matthew Group', made up of very gifted people..... He rubbed shoulders with the intelligencia until he found himself rubbing elbows; they proved to be just as frustrating as anyone else (they were appropriate provocation for An Island in the Moon; the Matthews Group had been relativized.
"I must Create a System, or be enslav'd by another Mans" (Jerusalem, 10.20; E153)
When Blake said that, it marked his realization that the systems he had found in Reynolds and the Matthews Group simply didn't satisfy his needs and values. With The Four Zoas he tried to systematize in poetry his own spiritual values; it led to universal incomprehension by his friends, even his best friends.
In 1800 he wrote to his friend and benefactor, George Cumberland, expressing his emphatic frustration over the commercial art he had been impressed into following, what he called the main chance:
"I myself remember when I thought my pursuits of Art a kind of Criminal Dissipation neglect of the main chance which I hid my face for not being able to abandon as a Passion which is forbidden by Law and Religion" (Erdman 706)
But the Magic Moment, the veritable rebirth came at theTruchsessian Gallery when he "was again enlightened with the light I enjoyed in my youth, and which has for exactly twenty years been closed from me as by a door" (Letter 51, to Hayley; Erdman 756)
The Four Zoas turned into those two masterpieces, Milton and Jersalem. But in general he moved away from 'poetry to painting' . Finally there were the Illustrations to the Book of Job; it might be called his Last Testament.