The need for them wasn't that widespread until recently.

Heating was relatively affordable. People on low incomes and the elderly had enough assistance to stay warm.

The British government have taken very little action in comparison to other countries in protecting the population from rising energy costs.

British homes are extremely poorly insulated compared to our European counterparts.

Many older homes rely on electric storage heaters which are much more expensive than heating with gas.

There’s a pretty narrow range of climates that need this kind of thing. Coming from somewhere considerably colder, if you don’t have heat particularly bad things happen and people’s houses are much better insulated. (The UK will never hit -40 which happens here more years than not, more or less) some people still have problems paying their bills, but not to the extent that you need shelters where it’s warm all over the place. They don’t by law turn off people’s utilities for nonpayment for several months out of the year.

My apartment is insulated well enough that if I’m cooking or have too many computers on it will get uncomfortably hot even on the coldest days. Having windows open because you’re hot when it’s considerably colder than freezing outside is an experience.