Those 20~30% are likely either a) appliances like people are mentioning. Stoves, fridges, etc. Which have reasons for being incandescent for which the law gives exemptions and b) old bulbs that would have inevitably been changed to incandescent anyway
I really think this law isn't going to make a significant difference in the % of incandescent bulbs over the next few decades. We're essentially going to transition at the same rate to a fully LED, whether the law existed or not.
So my question is - what's the point? We waste political capital and time that could be better spent doing meaningful things. And we can do things that don't arbitrarily restrict the choices of our citizens.
It's paying lip service without actually doing anything. Theatre.
Make our energy production 100% renewable and it doesn't matter in terms of carbon emissions if your bulb uses 4x more energy (of course ignoring production emissions, but just for the sake of rhetoric)