Bitcoin 21 million cap problem in the future?

Right now 16,382,250 bitcoins have been mined since January 2009 and some people think that probably 3 million bitcoins have been lost within the network and will probably never be found again and that got me thinking about bitcoins future in the years to come.

If bitcoin keeps being strong and still is used in like 80 years from today, what will happen when more and more people who hold a large amount of bitcoin die?
And not only people who hold large amounts but small amount as well?

Probably the price of the current bitcoins who ain't lost will increase as the one's who are "left" is getting rarer but when more and more people die in the future and more and more bitcoins is lost.... and that is going to be a problem in the future...

It is likely bitcoin will be replaced by another currency in the future but bitcoin will always be the "first cryptocurrency" and therefore I think it will always be demand for it, The sad part is that I think bitcoin is going to die even if we want it or not because of the 21 million cap as years goes by.

Robin