The deflation issue is what is really addressed here, where no new coins will be introduced at a given point. Whether new coin arrives or not, is really not an issue. An analogy would be the use of pennies if all the paper money went missing.
This would basically make Bitcoin Keynesian, since coin stored in wallets would now decay with a given probability. So you would have to invest it at least a little to beat the decay (shrinkage) rate.
Then you conflated losing some percentage of your cash assets due to inflation, which can happen even if the money supply does not change, to losing all of your cash assets with some probability. The former encourages investment, while the latter encourages not holding cash at all.
But when you have the private keys, your Bitcoin doesn't "decay". On the contrary, it becomes more scarce, and therefore more valuable.
Once the primary way of gaining bitcoins is hacking wallets, the longer a bitcoin is behind the same private key, the longer that given wallet is a target.