I wanna know how many years bitcoin can exist, because what if i invest a big amount and the bitcoin will go to shutdown or going to close a blockchain system. This is my concern.
bit coin can exist life long. bit coin is nothing but currency so how can it dissapear. now mostly people try to buying bit coins for their needs. so bit coin has great demand to day. suppose with normal money we have to purchase and invest in something in business like that bit coins also we have to invest like that. really it is good investment to earn profit. bit coin usage increases then it's life time also increases maximum bit coin not dissapear.
Life long may not be true, since after no real value will be gained from mining, it would be natural to see so drastic changes in whole ecosystem. Yes, it could still be used as some kind of limited currency thats is limited in numbers. However at the time when this happens there could be more alternatives with maybe more superior technology..
And even if all the blocks were mined. There is a chance that there are new ones being created as of this moment as a contengency plan. Its not necessarily bitcoin but another block would arise.