Those people who work online are almost all on bitcoin and so if online stores start to accept bitcoin then more people will buy stuffs from there , and with that other bigger companies will also adopt bitcoin to enhance their business.
Most people treat bitcoin as an investment that can give them profits everytime the price fluctuates. That is the reason why this currency has less regular usage compare to other currency when it comes for regular use.
And because that is the case, some merchants didn't bother to add bitcoin as one of their payment method since if we look in reality, it doesn't have been used much. Asked those merchants that already accept bitcoin and I will assume they will state that the usage is not that much for those using bitcoin directly to buy their products.