The lost coins are.. well.. lost. Forever.
And indeed, the remaining ones will become increasingly scarce. Which is a good thing, since this makes them increasingly more valuable.
And you should not be too much worried about this, since bitcoin works with 8 digits after the decimal point, so the real total amount of coins is 2 100 000 000 000 000 (satoshi).

We cannot even give the exact number of lost wallets. Some wallets have not been active since 2013, and it is difficult to even call them lost, as people can just keep them in storage. And of course, because the amount of bitcoins is limited to 21 million coins, its value will increase. Today there are many hunters to recover lost bitcoin treasures, and people go to various tricks, including even hypnosis, to remember their private keys, but there are very few lucky ones who could recover the lost ones.

This coins are lost and nothing will happen with them.
Bitcoin total supply is fixed at 21 million coins, circulating supply is around 18,684,000 but some research with FreeFloat supply is showing that 4 million bitcoins may be gone forever, and this can only be good for overall value and Bitcoin price.
Note that we can't know exact number of lost coins and some of them may be recovered and found in future, but people will probably lose more coins in future and bitcoin will be more scarce.

The Bitcoin lost cannot be recovered at all if you don't have access to your wallets or say you lost private keys for your coins. It's not that someone else will find them and take advantage of your funds unlike fiat btc lost simply reduce the total supply of 21 million coins.We have list of dormant bitcoin address with thousands of Bitcoin in them but we can't say they are lost or not because they are not active from past few years.Some people like German programmer who lost his 7002 bitcoins which are worth more than $220 million.Many in the past also has done the same mistake as they were not aware that btc will cross high level prices soon.


This is indeed making Bitcoin really scare and if people keep losing their private keys we might see actual suplly to be around 15-16 million only instead of 21 million.This will push the prices further high as demand will surpass supply with huge numbers as nobody will be willing to sell at that time.So if you are holding Bitcoins at this time keep your keys safe in cold storage and funds in hardware wallets to safeguard your future.

Yeah! things are not how you see it because the more it lost the more the value of each satoshi will increase and you cannot doubt that because a lightning network is developed for that kind of features. When people only sending satoshis in the future instead of the full amount of one bitcoin, you will realize that nothing has gone wrong. everything seems going to the right courses since it will give us good news and the price is our main concern here because the more we lost those total supplies, the more the price will reach its another all-time high.

Bitcoins are not lost, they just sleep in the system. The total supply of Bitcoin has always been 21 million coins. Fewer Bitcoins in circulation means an increased scarcity of Bitcoin. In my opinion, many Bitcoins have been sleeping in wallets in the past because users forgot the security phrase, wallet password ...
Bitcoin is more scarce after each halving.
Thus, it can be seen that there are fewer Bitcoins while the demand for Bitcoin increases over time, which drives the value of Bitcoin to increase. We can be confident that Bitcoin will be worth $ 1 million in the future.

I said earlier that there is no way to know how many bitcoins are lost.  Anything else is pure speculation.

Why was this post deleted verses other replies here?

If the coins will never be accessed or moved again, that lessens the number of bitcoins that will ever be in circulation , increases scarcity and price (assuming  demand for the coin outweighs supply).

I remember a thread here before asking how would one recover Bitcoins from a deceased person.
Thing is unless one is holding it from like a web or online wallet that offers it, there could still be a chance but good luck complying with requirements to prove relations and connections.
Well if it is something held wherein the owner himself holds the private key then there's no hope unless s/he left a private key somewhere written.