Hi Ian,
Your "question" is interesting but what you should really be asking is;
1. From a carpet owner standpoint , is carpet cleaning a luxury in an economic sense? If so, then economic theory will predict that "luxuries" will suffer at the expense of inferior products/services during an economic slowdown.
2. How do carpet owners interpret carpet cleaning in the first place? You have implied that carpet owners will clean their"old" carpets rather than purchase new carpets. Therefore using an inferior service!!
I would have assumed that, of course, if an economic downturn/slump was to take place carpet owners would be reluctant to replace their carpets as often.But this would apply to most products not just carpet.
However does the drop in carpet sales increase or decrease carpet cleaning turnover? I would think not because;
a. those that are particular about their carpets will continue to have them cleaned but will not replace their carpet as often,
b.those that usually replaced them rather than clean them are forced to have them cleaned.
c. those that view carpet cleaning as a luxury item will suspend the service until their prosperity will continue.....but the most important outcome? Carpet Cleaning will always be in demand no matter what the cycle...