I think its not necessarily that dividend yield stocks cannot build capital. Obviously you cant compare them to the high growth companies but to people with a preference for lower volatility a carefully selected portfolio with decent dividend yield can give good income and also capital appreciation in future. Few things which one should consider while selecting such a portfolio is only include companies where:
a) Dividend payments can be sustained in the long term (think non cyclical business)
b) Scope for dividend increases in the future and hence avoiding companies with unsustainable payout ratios