Just FYI, the main law is being broken is that the VoIP providers are unlicensed telecommunications providers.
In order to be a licensed telecommunications provider, your company must meet certain ownership requirements and comply with government oversight.
Part of the government oversight is the tariffs charged. Part of the ownership requirements ensures profit for the country.
Since the infrastructure to provide the internet is subsidized by international minutes (remember where the content, and where Saudi is) VoIP in its most common form is used as rate/toll bypass telecommunications fraud. Same like reconfiguring someone's voice mail to forward to an international number.
There is no technical reason why VoIP can be cheaper than what the telecommunications providers can provide. They could provide VoIP too or terminate the call through TDMoIP, lower codec quality etc... but this is whole thing is not about the COST of the call. It's about the margins and ownership. The telecommunications companies employ thousands of Saudi nationals. The Saudi nationals do not care about VoIP. This mostly does not effect them, it effects the expatriates. And even then, it only effects the expatriates who came to Saudi on contracts that don't pay them enough to make phone calls.
Skype has been typically allowed to operate in many middle eastern countries but only for PC to PC video calling. Skype-in and Skype-out services as well as access to the website to download and market the client was typically blocked.
Yes, the NSA scandal probably has some impact on the recent re-evaluation of Skype.