I'm 20 i search an investment for my 60, I found bitcoin years ago but bought my first satosh only in early 2017,
So i'm searching for a 40year investment, do you think crypto will still there or it'll crash before ?
  
-First : I think holding both alt and btc is contradictory for longtime investment(because of the correction), except for risk diversification but I'm more convinced in btc than any other coin what's bring us to the second point
-2nd : BTC becoming mainstream, most of people are not like us, searching the best coin etc... if the most known cryptocurrency work why go to the other ?
Because of transaction speed/fee? More/less coin supply? Smart contract ? lightning network ? they don't care and don't want to know
btc and all the crypto are deeply linked, if btc crash that's the end of crypto but if it continue to grow up crypto will too (but look the first)

I searched for a good store of value, i think it can be the best choice
but btc and crypto look more interesting for short time anyway
Like I said i search a store of value that can make benefits for my old days but it's not, it's a currency it can't be both
It cause incredible problems : actual circulation supply : 16,750,000 btc (around 2-4M unusable) , 16,750,000,0000,0000 satoshi
why establish it as a currency if it's price go up everyday ? why spend it ?
Imagine you as picking a bit of your gold bar every morning to buy bread. no that's dumb you use fiat

I dont believe anymore in the systeme because of the banker system, the debt , the derivative market, the creation of money ......without speak about politicians ..... I think everything is corrupt and is done to make rich richer

What's your point of vue for long-term ? In 40 years the cryptocurrencies and blockchains will be our greatest investment or will us loose all our money in a stupid bubble with all our family and friends telling they warned us