It's very difficult, particularly in a country with a mindset like the UK, to interfere with the rights of property owners. Even if the property owner in question is a right twat, they still have rights.
Say I owned a factory, or a garden centre, that loses money hand over fist for years, and I decide to close it and sell the site for development for several millions. Would that be morally wrong? Could the law stop me? How is a football club essentially different, except that there is probably more of an emotional attachment to it? Ultimately it's still property, not a sacred trust.
Labour is proposing to consult on tenants being able to buy their houses from private landlords at a "fair" price, and the mere suggestion is greeted as some sort of crazy Marxist outrage. So putting some magic legislation in to protect privately owned football grounds just because a minority are keen on football is going to be at least equally controversial.
As to other clubs helping - well, maybe, in certain circumstances. But why should well-run, successful businesses subsidise badly-run, failing businesses, especially when the latter may be run by unscrupulous conmen and asset-strippers?
The real solution for smaller clubs is to cut their coat to their cloth, ensure very good or excellent governance, and find a way to attract more fans to their niche product. It can be done, because Burnley and Bournemouth (to name but two) have not only succeeded at a lower level, but actually got into the PL.