I would disagree, some people have alloys costing £1k+, pretty much the same as a paint job in some cases. They are quite happy to buy a cleaner, polish, mitts, micro fibres, waxes and sealants to protect the paintwork which cost £50 in total and upwards but then baulk at £20 for a pot of C5 which will protect your wheels for 3 months. Seems like a good investment in the grand scheme of things to me.