While weddings can be costly in any region, they are especially important in India as symbols of strength and prestige. For many cultures, especially India, marriages are more than simply a union of two persons. A wedding marks the coming together between two families, lineages, and at times, bigger groups like whole villages or communities. Marriages are a significant rite (of) passage that signifies a person and their family's status.
To push one's financial limits at a wedding can, of course, be seen as an attempt to achieve a higher social status and respect within the wider community.
Matrimonial business appears to be recession-proof and is estimated to be worth $40 billion per year, growing at around 20% per year. Indians see it as an indicator of social status, so don't spare any expense.