There aren't as many options anywhere for good engineers as SF. Surely in Bangalore the big firms like Infosys and Wipro are always hiring experienced engineers?
Infosys and co are really body shoppers and working at such places isn't comparable to working at a product company. The pay, working conditions, project quality etc are (relatively) terrible.
The comment that there aren't many opportunities is wrong. If you're good and have been working at yahoo you'll find another job easily. But Infosys and Wipro are body shops, that's not a natural progress from working at Yahoo.
A bit more than twice the amount large consultancies pay. And these large consultancies recruit tens of thousands of employees every year, as opposed to product companies that have a total on a few thousand employees.
India is a very tough place to make a good wage even if heavily skilled. There's a lot of demand, sure. But there's an overload of supply.