Or businesses built around refurbishing existing gas powered equipment. You could end up having lawn mowers and generators where literally everything but the serial number tag is swapped out or rebuilt. Kind of like the infamous "Frankencars" of Cuba and the former Soviet Union.
They will implement either age limits or retrofit requirements for any engine built before a certain date or hefty fines. This approach is already used for diesels both on road and off road used in California. In addition there’s multiple companies that already retrofit small engines with fuel injection and catalysts making them as clean as cars with the same level of technology. California will simply say if you have a pre2022 SORE engine and it is not retrofitted than $1000 fine per incident per day. Send out a small ARMY of Gmen writing tickets to the lawn guys and compliance will happen fairly easy. Add in a confiscation clause where they impound the equipment until retrofitted this is done with diesels already. It’s not rocket science to clean up a lawn engine, a single ECU with an O2 sensor and throttle position sensor driven off a magneto holding the proper Air fuel ratio for the muffler mounted catalysts to light off and you solve the problems of NOx,CO,HC,ROGs and ozone which this law specifically addresses in the very text of the law.