I can't really speak for the automotive industry and I'm not sure how it's a particularly useful analogue but I appreciate the additional insight. I can only on the electrical world but generally anything installed on real estate I would consider to have more regulations and standards that could require skilled and certified labor. I'm sure anyone with some basic tools and determination could perform the work but that doesn't necessarily mean it's the best plan in every scenario. Generally my company will not talk to homeowners directly because the legal implications that you will inevitably find yourself in when homeowners decide to do their own electrical. I would imagine it's probably a similar situation elsewhere. If we want to get back to your analogue, a poorly worked on house would be much more of a sore topic than a poorly worked on house, especially when you're trying to sell. Hope that helps.