Number go up infinitely is due to inflation and that's basically just an incentive to not hoard cash indefinitely, and instead use it for something useful. But the only thing that uses up is numbers. Everything else is because people, on average, want more stuff and are willing and able to work hard to get it.
(Of course, this generally means that the markets chase the desires of those who have something valuable enough. People who don't will be marginalised by this mechanism, for sure. And of course there's lots of opportunity for people to steal or abuse powerful positions in the market to the detriment of others. Which is why a free market is not the be all and end all of organising a society, and other organisational structures exist to regulate it and to allocate resources in a less transactional manner)