Sounds like it is not common where you are, consider yourself lucky. Where I live, all new houses are built with predatory rental water heaters. $50-100/month forever. You end up paying the purchase price many times over. Electric tankless heaters use an insane amount of electricity when they operate. Overall they are more efficient, but the wiring needed to supply it will greatly increase the price, often requiring a panel upgrade and possibly an upgrade in service to the house.