The year 2015 so far has been somewhat harsh on the world's biggest retailer, Wal-Mart Inc.. In its second quarter, ended in July, the company reduced its annual earnings forecast range from $4.70-$5.05 to $4.40-$4.70 owing to wage hikes and e-commerce investments. But from the long-term perspective, these measures could help Wal-Mart survive in the fast-changing world of retail.