We know there will be at some point in time (estimated ~2150) a total amount of 21 million BItcoin in circulation. (minus lost bitcoins etc but all bitcoins will have been mined in the year 2150 or so
So right now we have a life expectancy of about 80 years.
So even if you are born 50 years from now you most likely won't be around when the last bitcoin is mined = when all bitcoins are in circulation.
We even know at what rate we can mine Bitcoin
So my point is, this leaves us in our lifetime with an infinite supply of Bitcoin.
That's faulty logic. The supply can't be
infinite since it's literally limited to the amount of circulating bitcoins. Right now, that is ~17.7 million bitcoins.
What you're pointing to is that the supply is still
inflating and will continue to do so throughout our lifetime. That's true, and it's why I hesitate to call Bitcoin "deflationary" at this time.
Same as with Gold. We still find and dig and mine for Gold daily, so we have a daily increase of actual Gold we can use.
Bitcoin takes things a step further than Gold. We can't know what the true gold supply really is -- we can find new areas of supply or new cost-effective ways to mine currently unreachable gold. There is no theoretical limit to the amount of gold. With Bitcoin, there is a predictable limit that we are constantly approaching.