This is mitigated via a proof of work "hashcash" mechanism, or for signed owners the ability of the CA to revoke the cert. BTW "high resource use" is in refere

This is mitigated via a proof of work "hashcash" mechanism, or for signed owners the ability of the CA to revoke the cert. BTW "high resource use" is in reference to things like tiny embedded devices. You won't be putting this in a fridge magnet or a smart light bulb. This will run fine on a $10/month VPS or a Raspberry Pi 3 or 4, though if the data set gets huge you might need to attach some storage.