It's almost like they are running a scam, isn't it?
They find some naive person who has just retired or been made redundant. They get him to sign up to an agreement which forces him to buy all his stock at their inflated prices, while also having to foot the bill for renovations, etc.
If the business manages to make money, they up the rent. If it doesn't, they keep the rent and prices exactly as they are, until the lessee runs through his redundancy money/life savings, then they take the pub back and try to find a new mark.