Loss private keys is not a concern on whether Bitcoin will last beyond this generation. Losing keys is an individual problem, while the topic of continuity relies on the adoption of both the masses and the government.
Given the Bitcoin situation right now, it is obvious that Bitcoin will last beyond this generation, I also think that it will even outlive the time when block reward becomes zero. The reason for this is that Bitcoin has made the government and companies get engaged with the Bitcoin Industry. This brings a more solid foundation than without these entities.
Now Bitcoin and technology are inseparable because they are bringing many new feature that are enough for us in long run, or we can say till humanity is going to exist because it's bringing financial independence on new highs, transactions happening just on a click from one corner of the world to the other, which was never thinkable. Despite having few concerns from governments, now changes are essential, and no one can stop this. It needs to understand and have enough knowledge about its positive use and keep things in balance.
A few things are having their own concerns, concerns such as lost keys or having glitches, but these human errors are possible to fix. Technology is making things on a dream level, and having policies about its use is having good encouragement, which is going to help for opening more new doors.
