Now, this will be fun, I used 10^11 parts.
Let’s switch out the numbers here
429.5 k quadrillion * 10^7 will give 4295 million quadrillion parts, or simply 4.295 septillion parts, i.e. 4.295E24.
To still be able to pay 1 millionth of a coin, with 2^32 supply, you need at least 4.295E15 parts.
4.295E15 / 4.295E24 = 1E-9
That means you can have lost as much as 99.999999 % of coin supply and still be good.
Losing 15% every decade for 1000 years, and you will still have enough coin left do do micro payments.
Now count in that humanity will not be as unexperienced as when bitcoin started out, and less will be lost.
Say 5% will be lost per decade, then we are good for almost 4000 years.
So there is plenty of room for safecoin to be backing all world economy, and doubling of the world economy many many times over, and still be able to do the equivalent of micro-dollar transactions for the coming 1000 years. Given of course, that we manage to stay alive for that long, and completely lose our human ingenuity so we come up with no better technology during these 1000 years.
Anyone worried?