Why it is different from any other OTC sale ? Because when you make btc OTC deal,you are buying or selling within the current supply,supply never changes,buy in ripple new supply enters the market during the Ripple's OTC deals,price drop shows the enourmous demand,cuz every penny goes to ripple while every xrp is going to market itself,today it changed.
I like your conclusion. However, XRP market dynamics are not this black and white that Ripples escrow sales are the only price driver. Ripple stated in the market reports they don't sell so much to significantly impact price. So no, XRP will not "moon soon" because Ripple stopped sellings for now. Also, they wrote in the last report that they will concentrate more on ODL-providers with their XRP, so supply may still increase. Also, 1 billion back to escrow does not mean Ripple has now 0 XRP to sell. They have a few billions in their pocket. Also, there's xSpring, funding project with their XRP war chest.