The scale is daunting...running new cables for probably more than half the households in the EU. Comparable to the effort to get fiber to the home.
Bigger restriction on that is how many people don't live in homes where they can just install a charger, but rather in apartments with either no charging or no dedicated parking at all.
I think the biggest reason for relatively slow adoption of electric cars in Europe is simply that most European are significantly poorer than most Americans, while also having to pay high taxes and fees. Median household income in Mississippi is almost 50% higher than median household income in France, for example, and this is compounded by higher taxes in France.