yes true.
Go and get a $20 serialised note and bury it in the ground. This is the same as losing your bitcoin wallet, like the $20 it is out of circulation for ever.
I once saw a link where it showed the unused wallets and the amount of btc out of circulation, cant find it now. However here is one similar. https://www.reddit.com/r/Bitcoin/comments/2twrs7/all_42400_dormant_bitcoin_addresses_with_a/
some other related links.
https://www.coindesk.com/meet-man-will-hack-long-lost-bitcoin-wallet-money/
https://news.bitcoin.com/guy-lost-bitcoin-computer-upgrade/
Bitcoin, however, can't be created indefinitely. Once every coin will be mined, there won't be any more creation, and lost bitcoin will remain lost, thus decreasing the whole amount of Bitcoins on circulation.