One major reason for the low clientele is the high price. If Civic price is just 2-3 lacs above GLI, more people will go for it but when that gap is above 5 lacs, thats a big amount of money considering that in GLI you can easily get a 'big looking' impressively built car. No need to buy Altis even as with a lot lower price you get the same shape.
@goku1: Even if new Civic prices are between 20-24 lacs, GLI customers too will consider buying Civic. It may not come under some people's budget, but there are plenty of others who have the budget for a +20 lac car but still buy GLI instead of Altis (due to the reason mentioned above). That's why sales of XLI/GLI is so high. From a personal perspective, its really hard for me to spend 23 lacs on Altis, when I get the same shape in 17 lacs. But I am still thinking to buy new Civic when it will launch. And many GLI owners too are thinking on that same pattern. Civic competition is with all the sedans in the market (and not just Altis).