What is the main reason why small town high streets are failing?

I think customer service isn’t great in some places. I went last year to a well known bookstore to ask about a particular book they had had in stock and was met with “dunno is it not on the shelf?” And no additional help. They said they wouldn’t be able to get it and then turned their head to the next customer quite abruptly. I wouldn’t want them to spend unnecessary amounts of time looking but they didn’t check on their system they just said no and moved on because anything else was too much effort. We have differing rights based on online purchases. If you buy something from a shop you rely on their returns policy being in your favour if you want to return it whereas online you’re covered by the consumer rights act. I live in the city centre but I know it’s £4 per hour to park in many car parks here so the combination of that cost, the fact most things are slightly more expensive like for like, the sometimes restricted opening hours, having to step over someone who has fallen on hard times to get into the shop and to then be face with poor customer service seems to add up to a very unpleasant experience which can be mitigated with a few clicks of a mouse. Of course, there are plenty of polar opposite examples in the high street. I got some great advice on rerouting pipework for my dishwasher and advice on what bits to buy from the local (not chain) hardware shop the other week and it worked really well.