Bitcoin have actually existed for 17years, which is equally more than half a generation and 2years. And because of that, I have no doubt that Bitcoin won't last longer again beyond a generation til a century time, because it has already proven itself for the last few years of being a trustworthy asset, and for the fact that it's last Bitcoin will be mined in the year 2141, which is more than 100years from now, it is enough reason for us to trust Bitcoin the more, and keep accumulating our portfolio, rather than worrying if it will last long or not. However, when it comes to people losing their private keys due to death, that's equally one reason that will make its value skyrocket the more when it's amount in circulation is now fewer.

Losing of password has being corrected and avoided by many who has lost before, and the new bitcoinners seams to be very careful when it comes to protecting their seed phrase and Passwords because of the value of bitcoin and it's worth

People are now wiser and more exposed to see the value and importance of bitcoin  than before and so they will also be passing on their inheritance with all necessary documents to avoid the lost of their assets because they don't know what bitcoin will turn out to be if they are gone in terms of it's value.

Only time will tell if bitcoin will continue but for now keep going on with how it flows .

If the BTC-creator programmed the source code so that the final block would be mined in 2140, they likely envisioned that this cryptocurrency would survive at least until that time.

Even if we consider this negative scenario, it will still be possible to obtain bitcoin through mining until 2140.

It will be much the same (nothing) as what has happened over the past 15 years; this won't affect bitcoin in any way, since only a fraction of the keys will be lost (just as has happened before). Personally, I’d add that fewer BTC-keys will be lost going forward because the attitude toward this asset has shifted, it is now highly valued, compelling owners to safeguard their holdings more effectively (with the exception of Coldcard users).

And just in case: quantum computers will help here.

The BTC-community will "print" new bitcoins. Just kidding. I don't think that (all bitcoins lost) will happen; I’d consider it far more likely that bitcoin would "die" due to a lack of internet and electricity during a global apocalypse than that all of bitcoins would be lost.

Are answers to these flights of fancy really that important right now? Perhaps it would be better to focus on the positive, that bitcoin is here for the long haul - and act accordingly?

Like I said, let's consider positive scenarios.

Your topic sparked a thought (also in the context of the fact that some bitcoins is lost, leaving less bitcoins available for purchase by future generations): how much bitcoins will future generations be able to afford? After all, the amount of this asset on the crypto market will dwindle with each passing decade, assuming companies and countries continue to accumulate and hold onto BTC-reserves.