This seems unlikely...even if the original core developers stopped doing anything with bitcoin others would take their place simply due to bitcoin's popularity and the availability of the source code. Even if the bitcoin popularity and development declined significantly it would not really die because the blockchain and ability to make transactions would still be there as long as we have the Internet. The only thing that would happen in such a case is that there would be fewer transactions taking place and the value of each BTC may decrease as demand decreases.