Why does Amsterdam have a lot of prostitutes ?

Because it has a red light district. Legal prostitution. Tons of tourists with money, and a lot of drugs.

Plenty of men ready to pay for their time as it is legal no need to be hidden away.

Prostitution is legal in the Netherlands, and it's considered a valid way to earn a living for both women and men, and your earnings are taxed, you get social insurance (sick leave, pension contributions, etc.). Prostitutes are required to practise safe sex and get regular health checks.

Needless to say it's not a job for everyone, but it can pay very well.

no more than in any other city

it is just that they are allowed to be on show , where other places make it a crime

Because too many stupid foreigners think that it is not as legalised and regulated in the rest of the Netherlands.

Same way they think weed is legal in Amsterdam, when there are hundreds of other places in the Netherlands where they can get it

Maybe they legalised it for tourist $.

every town has a lot but amsterdam has legal open street soliciting

it is a zone for working ladies