Because Labour failed to Undo Tory legislation under Blair as he grovelled to Murdoch. The further the Labour Party drifts from the Unions the weaker it gets. Until eventually it talks about the Unions as opponents (like Streeting does) and ceases to have a political faction to represent.

The Tories have always had landlords and bankers etc as their core constituency. Labour now only has the PLP caring about itself and breaks Machiavelli’s rules about patronage. They have no base to represent other than themselves.

The Unions haven’t grown weaker because people stopped caring about their working conditions. They grew weaker because of anti union legislation from the common enemy of everyone in the UK. @houseofcommons.parliament.uk