Those people who do home wiring badly continue to do so since such people tend to ignore all regulations. Those people who can do the job correctly are prevented from doing it. Generally retired people, they allow their electrics fall into a state of decay rather than pay an under-qualified 'certified' electrician to make a mess. This is a safety issue.
I am a retired electrical engineer. Any work I do at home (such as installing a new socket or re-wiring a lighting circuit) has to be certified by someone less qualified than I am simply because I don't have the hundreds of pounds necessary to keep my Certification up to date.
The death and fire rates from accidents have not reduced since this regulation was introduced. The only reason for the regulation was so that the Electrical Industry could make more money out of training and certification. It never was a major safety issue.