Although there are literally hundreds of blues guitar players coming mostly from the American South, only a relative few became known as big names. Of those, most became famous well after their deaths. A number of blues men were quite famous in their day, but were far from rich. So we have the dichotomy of fame on those days and fame as it's perceived now, which is a different kettle of fish entirely. Robert Johnson's name comes up again and again, but when he was active (and he died at the age of 26) he wasn't much known at all, just playing regional American music in bars up and down the country.
Most players moved up North from the deep south and perfected their art in the cities, very often Chicago. Big Bill Broonzy became quite a star in the 30s and 40s, often playing guitar with 4 or 5 different bands of musicians in venues all over the city to make a living. It was probably a hard drinking life with not much to recommend it except for excitement, liquor and women. Even Bill's talents couldn't stop him from falling from race when guitarists like Muddy Waters introduced the new electric blues music to the crowds. Broonzy was re-discovered in the 50s and enjoyed another few years of fame in Europe as a folk-blues artist.
Many blues men never made it past their 30s and we can only listen to their records in wonder, although some like Willie McTell, Scrapper Blackwell, Mississippi John Hurt and Reverend Gary Davis survived into their 60s. Interestingly enough, these men that had a huge impact on the blues in general and morn music later on, were not really famous. Blackwell was enormously talented and did enjoy some success as the guitarist half of a duo formed with piano player Leroy Carr, but he too fell into obscurity, being re-discover and making a few records in the 70s.
As can be imagined, many of the re-discovered artists couldn't perform as they did in their peak, simply because they stopped playing for one or two decades and tried to pick it up again, which never really works. Son House was asked to perform again and had to turn his back to the audience because of his nerves! One notable exception was Reverend Gary Davis, who never really stopped playing. He was obliged to play Gospel and blues guitar on the streets to make a living, sometimes teaching at home. Even at 65 he was playing stunning guitar in all styles and eventually made enough money to by a house in the West Indies to retire.