Yes, you could still punt without the internet.
As has been said already, prostitution is the oldest profession, the people on both sides of the transaction want it, it WILL find a way to happen.
But we live in the information society, never before have you had the means to make such 'an informed choice' - you can research a punt, see the girl's photos, ask for advice from fellow punters, read her profile, scan her feedback.
Will you always therefore have a good punt? NO. It's still a punt, and a big part of the way your punt goes - notwithstanding if she's either basically a 'good' SP, or a bad SP - is still dependent on your personal interaction with a girl.
But to a great extent, you learn to read the signs.
Also, I have no doubt that the internet has assisted the easy proliferation of prostitution for those that want to engage in it, punter or SP.