The shift in the meaning of Liberalism in representative government started in the 1970s as a response to Stagflation and Reaganism.

When talking about Liberalism in the context of modern western representative governments it now generally refers to the belief that liberal free market economics is the best way to a prosperous society (a rising tide lifts all boats, if people don't want something they won't buy it, the market has a role in government).

This is called the Third Way or Third Way Economics. This was when the belief that a good society is created by providing a good quality of life ended, and the new viewpoint that a good society is created through creating and protecting the best condition for business started (meaning deregulation, privatisation, a two tier legal system, privatization of profits, socialization of costs).

In terms of modern representative government, that's what liberalism now means. Liberals believe the protection of business conditions leads to a prosperous society and quality of life.

This put the government in the role of serving whatever businesses and industries said they needed, and we've been there ever since.