Sales and profit growth alone may not be enough to move a stock like Costco, which is already priced to perfection.Costco Wholesale (COST +0.26%) has been a top retail stock to invest in for multiple years. Although its warehouses require memberships, that hasn't deterred customers, even amid rising inflation. Renewal rates are often around 90%, signifying strong continued demand.Recently, the company posted strong earnings numbers, which yet again beat expectations, as sales and profits continued to be str ...