Let me clarify what I wrote: you have a choice between (a) just keeping the money, (b) buying some other kind of asset, and (c) spending the money in the real economy.

Asset prices can indeed go up, because people do (b), but (c) is almost non-existent, which is why these Fed operations are neither going to help the real economy nor create inflation there.

Keep in mind that those transactions are mostly done by insurances, pension funds, and other types of "money managers".