Rent is definitely a factor along with interest rates but the article talks about it “The key reason why is to do with how retail properties are valued, which comes down to what the asking rent on the property.”.
The issue is that if you were getting 1000/wk and then the tenant left you now have a temporarily vacant property if you lower the rent and get someone back in at 600/wk now your property valuation is 40% less which matters a lot for loans.
It’s also worth noting that commercial leases are often much longer so they might be waiting for a rebound in the market before renting it out.
Unfortunately this can lead to death spirals in a lot of areas.
Shopping centres might do that or offer other incentives maybe like paying for advertising costs or something. If the shops are owned independently like the article’s example then it’s a bit harder because they need to cooperate.