Actually way back dowry given to bride family is due to once their daughter married, she will be belong to the groom family. Even going back home would required permission.

Today is more like a form of gratitude & especially in current state of economic just give what ever you can afford. Marriage is not one off payment like before, after marriage might need to give monthly living expenses to both side parents, etc.

Furthermore, nowadays the chances of women involving infidelity is as high as men. No point splashing so much money in a single person. Better save some for yourself or your children in future.