Yup. I for one have not found any usable PZ space for the four TATL flights I have already taken this year or the four I have yet to take. (One time I did find some, but it was still a thousand or so cheaper to buy PE on BA with an immediate mileage upgrade to CW at booking.) And I see no point in gambling on the waitlist when you are almost certain to remain sitting in economy. It is important to me to be on a lie-flat on a long-haul flight. Some might be fine normally sitting in economy for 8 to 9 hours and consider getting a free upgrade one out of every ten times to be a real treat. But to me, it is better to fly on an airline where upgrade space at booking can usually be found (BA and AF).