Argos - the UK’s closest equivalent to Amazon. Why haven’t they challenged Amazon prime?

I’ve felt frustrated with Argos for years. Why can Amazon afford to do next / same day delivery for the cost of Amazon prime, yet Argos who have delivery vans going out every day can’t see that they could offer a monthly subscription for free delivery and plenty of Brits would consider using it? Particularly at the moment where many are considering swapping from US companies, this seems like a really good opportunity. Even if they only offered this to people living within a certain radius of their stores, it seems like it would be a great way to improve their business. Why have the powers that be allowed Argos to instead close their high street stores and seeming accept their eventual fall into bankruptcy?