As to what satoshi mentioned in his paper, his main intention was to use the electronic transaction without a third party and to prevent the double spending problem which was prevailing in the earlier predecessor of bitcoin (hashcash and b-money).
Not to be pedantic here but you missed the most important word out.
What is needed is an electronic payment system based on cryptographic proof instead of trust, allowing any two willing parties to transact directly with each other without the need for a trusted third party.
Transactions not having to trust a third party and being irreversible is part of it. My opinion here is that although it isn't explicitly stated in the white paper he went much further and didn't want to trust the creation of money supply to a third party either. Otherwise, we could have ended up with something like Tether. A payment system on its own doesn't require its own currency, but it does require trust in the issuers of whatever currency is used.
He has never discussed about the inflation, though he has stated that his main goal was to create a immutable currency. He might have thought that the capped supply could prevent inflation in the value and a stable price would be reached. But since miners receive the coins every 10 minutes, this speculative value won't reach a stable price soon.
He could have just as easily set a constant block reward of 50 BTC forever. This is what makes me think most that he had the intention of making Bitcoin a digital gold. There is a finite amount of gold below ground and as it is mined the easiest to extract gold comes in to supply and as time goes by it gets ever more difficult to mine the gold that is left.
It's just a personal opinion but everything about the design tells me this was always the intention. The words in the genesis block “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks”. It wasn't that banks were going to fail and depositors would lose money, it was that governments were devaluing our money to bail them out. We all paid for those bailouts.