It's been happening for a few decades. Out of town supermarkets moved out first, leaving towns without supermarkets. Then retail parks started taking out other chain stores like Currys, Halfords, WHS, Clarks, M&S etc. Now department stores are closing because they're an outdated model.
Smaller towns were hit first but now it's affecting the bigger towns and cities too. Even before covid, there were lots of smaller towns where the High Street was just charity shops, betting shops, Greggs, etc. and nothing else. People are only waking up to it because it's starting to hit the city centres which were previously relatively unscathed.
There's no going back. Retail is now "out of town" or online. Yes, maybe some independents will move into the High Street, but there won't be many of them as people will buy most of what they want on the internet or in retail parks, so basically, just "niche" shops, along with a sprinkling of "leisure", cafes/restaurants, etc.
High Streets and town centres will inevitably have to be re-purposed for housing (like they were before the chain stores took over the High Street), so whether that's by demolition or by conversion, it will be the future. The High Street of the last few decades will never come back.