So, just to make sure: the old Platinum signature visa which I have had for several years, still earns up to 5K pqm on united.com ticket purchases and another 5K after spending $35k? As I recall there used to also be another 5K on anniversary of getting the card, but am not sure it's still around. Is this right?

Just to answer myself: Just read the t&c on my statement for my type of card and it seems to say that you still get 5K pqm for $5k Ua.com purchases, another 5k for the first purchase after $35 AND 5k on the anniversary, But that United wont actually recognize more than a cumulative 10K, not the 15.
If that's so, why spend the $35k with this card?