When something is lost, it means you can not have access to it again, unless you luckily find what can grant you access to what you have lost. The possibility of losing your Bitcoin is if you no longer have access to your private key and it was an act that was very common years back, probably because Bitcoiners of that time didn't know that Bitcoin will become very appreciative to what it is today.
And also, among other things, happened when the various wallet websites and exchanges shut down, taking many people's assets with them.
Like Mt.Gox, BTC-e, or all of those blockchain.info wallets that were obsoleted by their new trading system.
Given enough time, lost coins will be reclaimed by technology that is able to claim them.
Only if said lost coins have had some shred of their private key or seed phrase exposed, or any other fragment that would allow signing a spending transaction from it.