What's the situation in the US? You're obviously not talking about direct cost,

    Mean house price: 
       London: $753,793 USD
       USA: $369,147 USD

    Average rent per month:
       London: $2,992 USD
       USA: $1,699 USD

Or being cramped into small spaces,

    Average home size:
       London: 705 sq ft.
       USA: 1,800 sq ft.

Or homelessness,

    Estimated homeless population (% of total population):
       London: 2%
       USA: 0.2%

Perhaps you are referring to comments on HN?

    Annoying comments about housing posted on Hacker News:
       London: Not seen
       USA: Way too many