Your stress shouldn't bother on the fate of others who lost their keys and their coins, neither should how long Bitcoin is going to last bother you so much that it may become a distraction to you. Your main interest at this time should be more about how much you can get and how well you can utilise the opportunities around Bitcoin now that you could witness Bitcoin, sometimes I feel we allow some little things stres us and distract us from the best that we can get.
So far we have seen Bitcoin continually improved and increased in value, we have also seen institutions and states beginning to consider Bitcoin, so all of that put together should be enough reason to believe Bitcoin is going to be around for quite some time, so needless of the fears of how long we will have Bitcoin around for.
If it were something we are not going to have around for long time, i think these institutions and states would likely not see a future with it enough for them to commit to it. Currently nobody can tell exactly how long Bitcoin is going to be around for and again, the lost keys and wallets holding Bitcoins that will eventually not be usable ever again will also impact supply which will in turn improve the value of Bitcoin for the best, so rather than bother about all of that, seize the opportunity to own a unit now when you can, so that by then, you will be counting your profits.
Despite having many bright features and things related to Bitcoin, few concerns and losses are also having a serious impact on Bitcoin because too many never trust anyone and have their keys safe, from where it's never been easy to pick them and have use of these coins.
With recent things going on, on the level is where people are thinking about why they are accumulating bitcoin and when they have their use. Also, it's never been easy to talk, but still now it's a point of talk. The existence of Bitcoin is always unquestionable because it's going to stay as much as technology is going to stay with us because now it's linked with this and no one can separate them enough. Negativity still exists, but it's never going to be a problem in the long run because Bitcoin's future is always on cards.