Real wages in the UK haven’t kept with productivity and growth. Real wages slumped after 2008 and have rose steadily since then but nowhere near enough to keep up with the increased productivity and growth. I read not too long ago the UK had the second worst real wages compared to living costs in Europe after Greece.
Yes, people earn more than they did 20, 30 and 40 years ago and consumer goods are more available but that’s largely due to the technological innovations. Everyone has a mobile these days. It’s pretty much accepted as necessary to have one today as much as an indoor toilet. But even though people earn more, the purchasing power of what they earn isn’t as great as it was decades ago. Rent is just one of the things that takes a larger chunk of people’s monthly earnings than it did 30 or 40 years ago. It was pretty common for a household of four to survive on one person’s income years ago. Today that’s really not possible anymore unless that one person earns a lot more than the average real wage.
Like you said, even people on benefits have access to smartphones and Netflix, technology so advanced that medieval kings and nobles couldn’t possibly conceive of. However, the wealth discrepancy between a peasant and a king in the 11th century was smaller than the gap between you or I and Jeff Bezos in the 21st century. So despite the increased economic growth and productivity, in real terms of wages, a person on benefits or minimum wage with a smartphone and Netflix is somehow even poorer than a peasant was 1,000 years ago.