Whether you brew it at home or take it to go, coffee is pricier than ever. (Michael M. Santiago/Getty Images)Make your coffee at home, they said. You’ll retire sooner without a daily Starbucks run cutting into your 401(k) contributions. But small indulgences aren’t the thing standing between many Americans and a comfortable retirement. That would be structural problems like the high cost of housing, wages that haven’t kept pace with inflation, and a fraying social safety net.