What many people don't seem to realise is that supermarkets make a loss on every delivery they make (around £5-£7) after they've paid for the people who pick and pack the order; then the driver; then the cost of buying and running the vans - it's far more profitable for them when people come into the stores and do their own shopping. They've been running their delivery service at a loss for years, which worked when only a small percentage of their sales were delivered, but over lockdown that's all changed. Personally, I still think £4.50 is a good deal - to save me petrol, AND my own time (both driving there, doing the shop, and driving home).
I've got another 'keen'... Ouch!