Due to the relatively high level of volatility associated with holding equities, it is hard to escape their gravitational pull on total portfolio risk and return.
Among public asset classes, equities are associated with significant risk (and expected return). Other exposures, such as interest rates and inflation, can certainly impact the total portfolio, but the magnitude stemming from equity is simply greater. Given how much risk is at stake, it makes sense to spend the time carefully thinking through and crafting an equity portfolio.