After seeing some dreadfull intrusions to the electrical system from tenants, I would suggest a yearly inspection which consisted of a visual inspection with minimal testing. In my opinion a experienced electrician should quickly be able to get a feel for any problems or interference to the system that should be investigated further, or be a reason for a full ECIR. This would have the benefit of low cost to the landlord and more likely to undertaken. It could be written into the tenancy contract stating that a tenant would be liable for the cost of any extra testing, because they have interfered with the electrical system.
I would suggest that a full ECIR was done every 5 years or as a tenant left, which would give proof that the electrical system was safe for continued use every five years or is safe/unaltered at the start of the tenancy.
For example, if any alterations by a tenant resulted in a fire, proof of liability would be traceable.
I think the problem with the landlords making sure that the gas ticket is kept up against the Electric is due to education of the general public. I would suggest that most people including tenants would know about the dangers of gas appliances whether it is due to gas leaks or carbon monixide poisoning etc, etc, and the need for regular testing and servicing is needed. How many people know about the dangers of electrical systems and the possible consequences, especially considering the amount of electrical appliances conpared to the gas appliances in a typical building!!!
I believe education of the public is needed or/and some sort of restriction of the sales of electrical equipment to untrained personnel is needed, I am not talking about someone replacing a broken socket ,and for the moment forgetting about the need for proper testing with a calibrated tester and understanding the test results!! That this person would replace the cables in the socket correctly and in the whole, the installation would be in a better condition than before. I am talking about being able to purchase every component from a consumer unit to a 50 amp MCB without the knowledge of the regulations or experience of how to install them.