Well, that's one man's opinion...
It is, of course, very convenient and simple to develop a world view if you're selective about the facts you choose. I will not posit mine here (no doubt suffering from similar flaws), but I can mention some things forgotten.
During the earlier periods, the salaries of the heads of corporations (latterly known as CEOs) was perhaps 7x that of the lowest paid worker. Today it is many hundreds of times greater, and even more so, if you factor in cheap off-shored labor.
Before 1974, salaries and standard of living rose on a near-yearly basis. After 1974, salaries (excluding corporate officers and factoring in inflation) remained stagnant.
Prior to the 60's, most families were supported by a single (usually male-earned) salary. With the advent of the women's movement, women who felt they'd been getting the short end of the stick, entered the workforce in great numbers. Now, it's common — even necessary — for multiple paychecks to support a a family. It's my belief that while those 60's white male-based employers outwardly responded negatively, in secret they rejoiced at the near-doubling of the workforce, especially with cheaper labor. (Even today women fight for equal pay for equal work.) The trend for off-shoring continued the joy as corporations raced to the bottom to find the cheapest labor. (And why wouldn't they? It is the sole purpose of corporations to profit.) This played into the breaking of union power (which was not helped by some apparent corruption among unions — I'm looking at you, Teamsters.)
American wealth was boosted by huge infrastructure projects, not least of which was the National Highway System, which fostered trade and travel with it's concomitant growth effect on the economy. This was paid for with taxes. Somewhere along the line a general tax revolt ensued, egged on by the rich who admittedly bore a large burden. Without taxes and with the addition of huge defense expenditures (military-industrial complex, anyone?), today we are faced with crumbling infrastructure, which we could rebuild, but those think government should pay for nothing but defense object and we are at a stalemate. Obama's plans for such came to very little.
The Glass-Steagall Act was an attempt to protect the ordinary citizen from predation by monied interests. Even though Roosevelt (decried as a class traitor and blamed for just about any and every governmental or economic ill that ensued by my right-wing friends) was cool to the idea, it became the law of the land until it was repealed under Bill Clinton. (For those unaware, among other things, it prevented the combination of commercial and investment banking.) Not too long thereafter, the world suffered what we now term 'the Great Recession,' caused in no small part by those banks playing money games with the economy (there are many good histories of what happened.) We need mention only in passing Credit Default Swaps; slicing and dicing unsupportable mortgages as investments which the issuers, themselves, bet against; and interest-rate rigging — though of course there are many issues as deep. Average Americans suffered dreadfully and were further taxed with paying for a bailout. Those banks (the ones that survived) did very well, thank-you and their officers, even better.
I'm quite sure there's more, but I've gone on long enough...