Hi Edward,
I am in the same situation as you. I first came to realize all effects were not working after buying several effects products from FSFX Packages. I spent weeks trying to figure out why all effects were missing. The best I can tell LM made a change starting in Prepar3D V3 in how effects are rendered that does not work with certain video cards. I tried every driver I could get my hands on (including beta drivers) for my AMD ATI M8900 card and could not get the effects restored. Then I started working my way backwards from P3D 3.4.22 doing fresh clean installs with no addons. As soon as I did a P3D V2 install the effects were all back and working. From there I started doing clean P3D V3 installs on a different machine I had available with an AMD ATI Radeon R5 240 card. In some versions the effects were there and in some not. I always tested them at KLAS (Las Vegas) at 2200 hours. All you have to do is look over at the strip and you shroud see the bright Luxor Hotel Sky Beam light and a fireworks display occurring. In P3D 3.4.18 the light and fireworks are there, but in 3.4.22 the fireworks are there but the light is way up in the sky instead of coming off the point of the hotel. My greatest hopes are LM addresses this in a future build.