To give Rajnikanth is due credit, he is the most loyal actor; he is slavishly loyal to cinema, as an art. He doesn't take the success earned from films to sell insurance policies or biscuits. He doesn't go on television, barging into our living rooms with serials, reality shows or brand endorsements. He has maintained that respectable dignity - a sort of total professionalism and commitment to films. He won't sell us under-wears; but if he wears a red one and flaunts it on-screen, the world be damned, we will follow suit.
Amitabh Bachchan perhaps had other reasons to get into the 'brand ambassador' and television personality roles. After all, the man was on the verge of financial ruin. He perhaps had to pick every lifeline that was thrown at him to salvage his books. He has never looked back since; he endorses virtually every product and if you miss him on television, he is on Twitter, anyway.