Sure, PKI has serious problems. But HTTP without HTTPS has far worse problems. Nothing is perfect. Waiting for the perfect, while failing to help in easy ways that you can do now, is a poor choice.
In any case, HTTPS doesn't protect your site, it protects the users of your site (by protecting the confidentiality and integrity of the data in transit). If you don't care about your users, then those potential users should avoid your site.
MITM attacks have become pervasive. HTTPS was less important years ago, but that time has passed. For example, ISPs, hotels, airlines, and many others have decided that it's okay to attack their customers. Supporting HTTPS is an easy way to help those users. It doesn't need to be perfect to be useful.
In any case, HTTPS doesn't protect your site, it protects the users of your site (by protecting the confidentiality and integrity of the data in transit). If you don't care about your users, then those potential users should avoid your site.
MITM attacks have become pervasive. HTTPS was less important years ago, but that time has passed. For example, ISPs, hotels, airlines, and many others have decided that it's okay to attack their customers. Supporting HTTPS is an easy way to help those users. It doesn't need to be perfect to be useful.