Apparently much of the music we have retained from the Baroque/Classical/Romantic period was written to be performed for or by a generally upper-class audience on expensive instruments. How much of this music would have been familiar to and/or played by commoners?
Would you catch a Hampton hooper humming Haydn? A Swiss smith singing Strauss? A Bavarian blue-collar band borrowing chamber music from Bach?
You have read correctly! We get this question with some frequency, but your alliterative examples really hold it head and shoulders above the rest.
There are a few ways in which the Salt of The Earth might have experienced historical art music. One, and this is a big one, is church, which had expensive music free for the hearing. While this is only a slice of art music available at the time, it would be a way to hear some of the work of modern composers in your local area. Becoming the local official music master of a church was a valuable mark of status as well as good money. Handel, Hayden, Bach, and many other bigwigs were Kapellmeisters for churches or for courts.
Now, let's say you want the cream of the crop, you want the most luxurious expensive music around, you want opera, but you're poor, so you can't buy even the cheapest ticket, which is usually more than 2 or 3 days wages for a normal person. Okay, here's some ways to get in.
1.) Be a servant. In Italy it was customary to bring your servants to the opera, and they couldn't help but hear the music. In some opera houses, most famously La Scala, it was customary to let the servants stand in the back while they were waiting and not needed. Be warned that in France this was not the custom, in the Royal Opera House in Paris no one was allowed to attend if not properly dressed, which excluded servants in livery.
2.) Be a claquer. Claquing was the practice of having hired fans come to your opera and cheer their employer and boo their rivals on stage. These people had free tickets from the person who hired them. Sometimes they were more spontaneous in their affiliation and not expressly paid for their attentions, but they usually were compensated.
3.) Be an expensive prostitute. Opera houses maintained "free lists" which were lists of people who got in free. Some of these houses had rolls of local good-time-girls who would hang out on the floor in front of the stage, where the young men with money liked to hang out. They were part of the overall offerings I suppose, along with the wine, gelato, and faro in the lobby. I've read about French prostitution from the time and never seen anything about if they liked the opera though!
4.) Be a gondolier. Only works in Venice, but they were customarily on the free lists in the 18th and 19th centuries. They would tell their customers (usually people with some money and tourists, Venice was a tourism city then) which operas were hot, which singers to look for, maybe even try singing their own version of the popular hit aria, etc., which made their custom valuable advertising. They would also join up with claques for some extra pocket money.