I've seen this recently on a number of stays across various hotel brands in the US (not limited to IHG)-- only two bath towels placed in a room with one King bed.

I don't think it's just cost cutting-- could be also a way to manage labor shortages. I stayed at a fairly upscale hotel in SF recently (that actually did have daily housekeeping!) and was surprised to return to my room to find that the housekeeping staff had removed my used towels but failed to replace them. When I found a housekeeper in the hall to ask, she explained that they were having delays with laundry and that replacement towels would be brought to my room as soon as they were ready (which they were a short while later).

Of course, it's ridiculous that this property would not provide additional towels on request.