I have considered how a well-kept lawn and a yard devoid of weeds and autumn leaves are symbols of social class. Are Christmas decorations similar markers?

I would say the majority of suburban single-family homes feature no exterior Christmas lights. By that measure, having lights is not the same as having a neat lawn. In many suburban neighborhoods, it is a necessity or requirement to keep one’s lawn cut to a reasonable height. Of course, people of certain means or tastes can take more care of their lawn and landscaping beyond just the basics of what is required. Similarly, many homeowners will take care of many of their leaves while those who desire to get rid of every leaf will take the extra steps.

Perhaps Christmas lights then are more like dealing with weeds. The homeowner who wants to keep up their property values and/or contribute to the appearance of the neighborhood will eliminate weeds before they even sprout (rather than addressing the issues as they arise). Christmas lights are a nice touch but not necessary in the same way as a green lawn.

Christmas lights may not function in the same way as these other exterior touches for several reasons:

1. The Christmas season is relatively short. Some might get a head start on lights and decorations before Thanksgiving but the full seasons of lights is probably about six weeks long (Thanksgiving through New Year’s). In comparison, people have green lawns and growing plants for months.
2. Not many homes are sold at this time of year, particularly in colder climates, compared to other months, particularly the early Spring to mid-Summer window. Thus, Christmas lights have a more limited impact on property values (and may not be remembered much at other times of the year except in egregious cases for distasteful decorations or displays that draw too much attention).
3. Not everyone celebrates Christmas. (I suppose the flip side of this is that many homeowners celebrates lawns or nature or spring/summer or something like that. Or, maybe they are just bored.)
4. There is not the same cultural importance on Christmas decorations for homes compared to the long-standing interest in having a green lawn from the beginning of suburbs to Levittown to today.

In sum, Christmas lights and decorations do not matter as much as lawns as markers of social class and property values. Those with more resources can put together larger displays and might veer toward more aesthetically pleasing displays than those without resources or different tastes. Given the commercialism of Christmas and the decreased emphasis on lawns, could there one day be more interest in Christmas decorations than a well-maintained lawn? This is a long shot…