Almost every time I bring up Bitcoin to someone new this question arises.  I think it's an important topic but difficult to give a solid answer.

this is a good thing afterall, the more they are the better for the price if everything else remain the same

anyway it was estimated that they were around 3M at least, i don't remember where i saw this now

Impossible to know... but when they were nearly worth nothing in the start, lot of them were lost for sure.

Yes, we can't be sure of the exact number of lost bitcoins. But:

1. It is not important.
2. It is actually a good thing that bitcoins are lost.
3. Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone.

Here's a thread from 2011-2014 that tried to count all of the bitcoins that were permanently lost (and not just merely stolen):

http://bt.irlbtc.com/view/7253

One example that comes to mind is the Counterparty proof-of-burn which saw 2,130 BTC sent to an unspendable address. Then there's that hard drive containing thousands of BTC that got thrown away as well. Those coins definitely won't be going anywhere anytime soon. But like others here have already said, I don't think we'll ever know exactly how many coins are truly lost.

I'm sure there are also people out there who will claim that their coins are lost when in fact they still have access to them - either because they're scammers who want to hide their bitcoins or simply those who want to avoid taxes on their BTC income/wealth. Then you might have people who end up dying with the only copy of their wallet's encryption password being the one stored in their head. There would be no way to prove whether or not these coins are actually lost.

This has to be impossible to assess realistically or with reliability. The anonymity enables each coin outstanding to remain unlinked to a source or person. Further, even if we could assign an owner to the coin we wouldn't know if the coin was lost or just being held.

Certainly a great question. Is there any way to see the count of coins that haven't had any transactions from or against it over a long period of time?

I'm afraid my spider sense only stretch so far.

The most likely losses are from the very earliest days. Lots of people on here have written about mining on their computer, not liking what it was doing to it and deleting everything. At the time their computers were worth a vast amount more than what they were mining.

You've also got no shortage of newbies from all eras making a balls up with their coins. Even veterans have made massive mistakes. Bitomat lost the private keys to 17,000 of their customers' coins.

Someone summed up the lost BTC only from the thread. In total BTC 134578.27864659
And this is likely just a particle of all lost coins.

https://bt.irlbtc.com/view/7253.msg8601641#msg8601641

ahh such tricky question:)

14.3M mined, from them were 740k goxxed...adding bad luck, human factor and stupid RNG. ok, lets say at least 3M until now...maybe even more.

Why does "everyone else in the world" lose out?
1) There will always be enough BTC, since you can add more zeros and someday buy an awesome new car for 0.0000000000001776 BTC.
2) The eventual race to own "at least one whole Bitcoin" will drive prices to levels that might (today) seem very insane.

Edit:
3) High prices do not drive people away, just wait until you see your first Bull market, Newbie.