Ok I understand. You're running a laptop. Then sorry you arent going to be able to get p3d v4 to run at anything other than at a single frame frame rate. I have tried. I am running a 2.2 ghz laptop with a radeon 6600 M with 8gb ram. ( full disclosure I now run linux with xplane on it and rarely play x-plane, normally WH40k ) but I got 4 fps with our electra ( the stock one ) which is middle of the road and far lower spec than the sabreliner is going to be.
I dont think there are many that cant run p3d ( laptop users withstanding ). There are a few who dont want to, however (and this is going to sound harsh ) they are also not likely to want to spend the coin that a developer would charge. See even if it is for a previous simulator, the time/effort/skillsets required to make it will be the same - if not more - therefore the price will be the same as the P3d version. And there is this odd notion that because the sim is so old the pricing for addons for that sim should also be low. A bit like what is happening on steam right now with FSX:SE. The addons cost more than the sim and wow the community on there is certainly vocal about it!
So the return on investment is such that it simply doesnt make sense.Which is why i see FSX having a resurgence in freeware authors, like what has happened in FS2004. As payware devs switch focus more people come in to fill that vacuum. So in the end FSX actually starts to get more content and at a price point no-one can disagree with ! Win-win situation.