Bitcoin going to zero is also a possibility but it might never happen which is because the adoption of Bitcoin keep growing every year. More and more people are believing in Bitcoin and buying it so they can make future profits.
It is impossible to be zero because of the interest that still exists and also the level of interest that over time is increasing in Bitcoin. So it is possible to be zero if the level of interest in Bitcoin has decreased over time, but what seems to be now the interest is increasing to the point where there are countries that have adopted it for legal payments.
With the increase of interest in digital payment by the government, Bitcoin chances of going to zero has been reduced. The price can only dump but still it'll have value as we'll be having buy orders waiting on a price drop to get filled.
This is also a very logical and concrete reason for now because with the increasing number of digital payments that have been implemented by many countries in this world, of course there will also be better opportunities for Bitcoin because Bitcoin is also more digital so that its life will be longer and away from death or becoming zero.
Bitcoin isn't not built like the other fiat currency that inflation can make them become worthless. Bitcoin is built in a way that the project has to keep on increasing every four years after halving is completed.
And this is part of the advantages that Bitcoin already has so that Bitcoin looks different like any fiat currency. In addition, this also makes Bitcoin valuable and stronger in general so that the effect of being zero is very slight, especially since the people who are interested in Bitcoin are very varied in this world.