I think that the majority of operators and 100% of passengers who have ever been repatriated following the demise of an airline would agree that the CAA ATOL Bonding scheme is a good idea.
There have been enough dodgy geezers who've tried to start and run airlines in exactly the manner which you advocate, hence the rules and regulations.
If the industry wasn't as heavily regulated as it is, ther'd be far more rogue operators leaving more suppliers and customers high and dry.