A bit of a conspiracy theory here, but I wonder if this isn’t starting to become deliberate? If you do a competent job and do a proper restoration then–unless it’s the Mona Lisa or the Sistine Chapel–basically no one even really notices.
Whereas if you botch the hell out of the thing, you–and the venue–both become famous! Granted, it’s the sort of fame that mostly consists of people pointing and laughing, but for some people, any kind of fame–even infamy–is still fame. (“There’s no such thing as bad publicity!” as the old saying goes.)
And what are the real consequences here? It’s not like anyone is actually being sent to the Art Restoration Re-Education Camps. You and the venue become a funny Internet meme; people probably come to see* your “restoration” and maybe even buy a T-shirt or a coffee mug with a picture of Potato Head Jesus (or whatever it is) in the gift shop.
*Pre-COVID or post-COVID, that is.
Fucking up a one-of-a-kind piece of art is the main consequence I can think of. Assuming the damage can be repaired, it means a lot more time and expense for the actual expert who must now restore a piece of art that’s in much worse condition than it originally was.
Given that the article says that people are calling for stricter oversight, I would say that Spain probably does not have very strict oversight.
I know that in at least some of the European nations, there are historical oversight committees that have quite a bit of power when it comes to any work or restoration on historical landmarks. They can fine and sometimes even prosecute contractors and workers who do substandard work. There are actual qualifications and licenses required of anyone who is going to do such work.
I would assume that Spain does not have such an agency, or if they do, it doesn’t have any teeth.
What I like to ponder is, how did it feel for the artisan when he/she got to the point of thinking, “Hang on, this isn’t how this should look.” I’ve botched enough repairs/touch up jobs to be familiar with the feeling that you have just gone one error too far, but never with anything important.