Significant extra cost and/or degradation of life style to ordinary homeowners.
Building Regulations are currently used as a method of increasing cost to home owners. Where a new item is to be installed, then the regulations can apply but they should not apply to replacement items. For example, I had to replace my oil boiler and it could not be installed under current regulations in the same place as it had been installed. Considerable replumbing was necessary to get a replacement to what had been working well for 20 years.
If I wished to replace my oil tank, then it would not fit into my property under current regulations giving clearance to boundaries etc. I would have to move away from oil and propane gas and only Electricity would comply with current regulations.