Life style of socity wasnt tough that time , like it is now. That time, none had to have medical insurance to stay alive and our countries hasnt got any fund for widow people(woman working is seen as very negatively also!). Saying things are easy hadhrat, but practical life is different. And marrying more than one was tradition of arab before Islam came. So keeping the tradition as allowed doesnt mean you are into Islam totally if you practise polygany, and you arent in Islam totally if you didnt married twice-thrice.