I see them shrinking both. I figured they would want to do the Pro first, but considering the OG model is making up 75% of their sales, they may want to get the price down as low as possible to bolster the dropping sales. My guess is a $249 price this year, but they will definitely drop to $199 for the PS5 launch. And we may see a further drop to $149-$179 before it's discontinued in 2022/2023. The Pro will probably drop to $349 without a revision, but my guess is they also want to get the price lower on it, so it will get one the following year.
They could have a $199 PS4 system for budget gamers, a $299 Pro for those who want a little more power under the hood, and the premium $449-$499 PS5 for those who want next gen graphics. All 3 will get cross-gen support for at least a year or two, so there really isn't a need for them to have a weaker next gen system to compete with the Lockhart. And by the time the PS4 is discontinued, PS5 will see its first price cut, probably dropping to the $399 sweet spot.
The rumors for Lockhart tend to be a $299-$349 launch price. Officially pricing Pro at $349 by then could work, depending on the Lockhart specs, as long as they are similar on paper. That way you would have a $199 PS4, $349 Pro, and $499 PS5. All consoles being separated by $150 gap. Depending on Lockhart, they may want Pro down to $299 and profitable, which could be a 7nm slim model for E3 2020, out before the PS5 during the holidays. This may help to stay below the Lockhart launch price, and would also make PS5 look like more of a leap with a $200 price gap. Then again, PS could just go with another 2.3X increase and land just below 10TF, possibly hitting $399 for PS5, making an even $100 between all consoles. This should allow PS to hold those prices for the next 2-3 years without changing the hardware at all.
With the mention that PS doesn't seem to feel the transition to PS5 will be as fast as PS4, do we take that as meaning the PS5 will be $499 and so the price won't be that attractive, or possibly that the hardware jump (in TF) won't be as substantial as some may hope or want, and so they won't feel the need to upgrade from Pro for slightly better res and faster load times? If only 1 in 5 PS4's sold is a Pro, PS may assume a $399 PS5, considering it will be seen as another upgrade and not a new gen since it'll be heavily tied to the PS4 ecosystem, may not see the same kind of sales PS4 did. Not to mention years of cross gen games. Maybe PS5 exclusives won't be ready for a couple years after it's launch, also leading to slower sales at launch?
There is also Lockhart at 4TF to really take into account. If MS really ditches XB1X at 6TF, and launches Lockhart at 4TF instead, what does that say to PS about launching a $500 power crown console that get's dropped just 2-3 years later? It would solidify that Pro at 4.2TF was the better choice, which launched at $399, so maybe PS will stick to their $399 premium labelled console. Focus on CPU, built in VR, SSD loading speeds, and if that means a 9TF GPU then so be it. You will get some PS4 and Pro owners to upgrade, but as long as they are still buying the cross gen games, who really cares, as long as they aren't leaving for XB.