Well, then you also have to ask yourself these?
How big was the first ever mineral mined?- it's still existing and being mined for more profits..

How big was the first ever university?- it's still functioning

and many other first discoveries or inventions functioning well.

Your assumption may be true but that doesn't justify that Bitcoin will die. There is evidence of first discoveries existing.

And don't forget that many of these altcoins depend on bitcoin for survival...There's no crypto without bitcoin