bikingshearer 

The average pro still made more than he would have in the fields, the mines or the factories. It was the savings from being a pro that gave some them enough capital to open a bike shop, a bar, a small restaurant, etc. when their careers were over, usually in their home town or home area to take full advantage of their local fame. A career as a gregario could lift the rider and his entire family out of poverty and into the merchant class - a very big step up for many, and the reason other family members would sacrifice to give the cyclist better food, decent equipment, time to train, etc. Pro cycling drew most of its riders from the same socio-economic pool as boxing and baseball did in the USA - the urban and rural poor. It was never an easy way to make a living - it still isn't.

You are absolutely right - for the average pro, they were not going to get rich and likely had to scrape by on their regular pay (assuming the team actually paid them - far too many racers got stiffed when it is was time to collect their pay envelopes. Salaries were paltry for all but the Coppis, Bartalis and others in that stratosphere. Most of the riders had to have off-season jobs, and most had to race as hard as they could in as many racers as they could over the entire season. The real money was in (1) endorsements (increasingly so as the years went by) and (2) appearance fees at post-Tour criteriums and six-day races. One of the ways a team leader insured the loyalty of his domestiques/gregarios was to make criterium promoters include some of the leader's lieutenants and pay them an appearance fee, too. Just as the brighter lights got higher appearance fees, so too they could negotiate to bring along a greater number of their domestiques.