People didn't have fancy sneakers but shoes were usually made with a Goodyear welt to be rebuildable and long-lasting, and such shoes usually cost hundreds of dollars today. Sears and similar stores sold durable, American-made clothing— visit a vintage store some time (acknowledging survivorship bias, though).
Houses were also small in 1950 because the housing pipeline was essentially clogged up from 1929 to around 1950, due to depression and war. Housing also was a much smaller percentage of most families' consumption baskets at that time, as well— there was a lot of buildable land at the edge of major metro areas, and the capital-GDP ratio was low so asset prices were low.
Working-class (evolving into lower-middle-class) employment was much more stable in 1950, and stability is a big part of being middle class.
It's not really possible to live a 1950s lifestyle today, since a significant proportion of lifestyle comes from living around, and being respected by, peers. And from the better availability of stability in employment, which one cannot get via personal finance.
But ~40% of the population lived in rural areas, and what I understand from relatives who lived there during that time, travelling to town was considered a luxury. Today, nobody thinks twice about hopping into the car and going to town every day.
Not everything in life is about possessions.
http://books.google.com/books?id=SNkDAAAAMBAJ&pg=PA178&dq=sm...
http://books.google.com/books?id=xdwDAAAAMBAJ&pg=PA65&dq=smo...
Now, it's true that pollution is still generally worse in poor areas compared to wealthier areas, but the pollution issue alone makes me prefer a "poor" lifestyle today over a "middle class" one from 50 or 60 years ago. We also have additional consumer protections for food and medicine compared to 60 years ago, which makes it hard to compare products across decades.
Homicide (and presumably other violent crime) is about the same as 1950.
Further, "poor" people have always had lower social status and higher stress, so there's no change there.
In 1950 it wasn't uncommon for people to still use outhouses and not have electricity.
Life expectancy reference: http://esa.un.org/unpd/wpp/unpp/panel_indicators.htm
homicide rate reference: http://www.infoplease.com/ipa/A0873729.html