You'd have to be naïve to assume the standard of living in Western countries today is comparable to how it was in the 1950s.
But, if I look at my parents, who were raised in "average" middle-class families in the US, there are many ways today's families' "standard of living" is worse, despite the fact that they can buy a lot more shit. 2 simple examples:
1. There is a ton more obesity today, and it has a disastrous effect on standard of living.
2. There is a ton more anxiety about maintaining a standard of living. My grandfather worked for "Ma Bell" for 47 years and raised 4 kids on that single salary. They ate dinner together as a family every night. Today your "average" middle-class family has both parents working and still with a constant undercurrent of economic anxiety.
Look, I'm in no way arguing the 50s were some idyllic "Leave it to Beaver" utopia, but I am arguing that once you get to a "comfortable" middle class existence that focusing on "ability to buy more stuff" as the primary driver of "standard of living" is a mistake.
#2 was unique to the US. The rest of the world was either in shambles from colonialism or from WW2. Factories were destroyed and the US produced much of the world's manufacturing output. This temporarily gave a huge boost to American industry. As other countries recovered, competition became stiffer. Moreover the US labor market at the time was compromised almost completely of white men, so there was a lot less labor competition. The story was very different for others.