What's the difference between Lotus (and other generic storebrands) dishwash and branded dishwash such as Glo and Sunlight?

I always use Sunlight. 900ml bottle is around RM6.50 these days, 700ml refill around RM5.00.

However was flipping through The Star newspaper and saw Lotus generic 1L dishwash bottle at RM3.80. How come larger capacity but so much cheaper?

In fact, same can be seen with other household products, such as tissue box, tissue roll, kitchen roll, hand-wash. And it's the same with other supermarket chain. I see Hero Market also has its own generic detergents etc.

So my question is, why are generic products so much cheaper than branded ones? Is the quality inferior, is it made of more dangerous chemicals, etc.