No it usually comes down to seed quality IF all else is equal (temperature, soil, water, etc). Generally chinense take longer than annuums but beyond that it might have been old seed, or seed subjected to excessive temperature (generally above 100C), or with mold spores on it that attacked right away, or too much moisture in it then it froze, or the pod was picked too prematurely so the seed wasn't mature either, which can be misleading because the start of bacterial infection can make a pod start turning a ripe color before it had a chance to fully mature.
Give them more than two weeks, I often have some take between 2 to 4 weeks then give up at 4 weeks... providing it stayed above 80F daytime and 65F nighttime.