Passat, cupped tires

Hi

I have a 99 passat and it is destroying tires, on the left side (seems
to be front) The technician says they are "cupped". You can run your
hand around the tire and feel the tread go up and down. This has
effected the stock tires, and the set of summer tires. I had the
alignment checked and they said it was off a little bit, but within
spec. (vw dealer) I have had several linkage pieces, a bad lower
control arm/cv joint replaced on the front left. Is there anything
else I should have checked before putting new tires on?

thanks