You have no idea kid!
This is the image of New York taken from the International Space Station, 400 km away from any point on Earth (that is directly under it) and travelling at 27000 km/h.
So I heard you say low-res camera? You must be blind if you call this low-res in spite of the distance and speed of the ISS.
First off, the camera specifications are driven by science and system requirements. If we need a high-resolution camera, the science that we want to do with it shall require it have such a resolution. Otherwise, we are wasting mass and power, two of the most precious resources for spacecrafts.
And did I hear you say “no video”?
Have you heard of the High Definition Earth-Viewing System (HDEV) placed on the ISS? Here is a link:
This is the live stream of Earth’s view from the International Space Station.
This space is too short to mention the entire specifications of cameras used by NASA spacecrafts.
If you are interested in Voyager 1’s wide angle camera, check these specs: Ring-Moon Systems Node.
Voyager 1 was launched in 1977 and here are some of the images taken by it.
Additionally, these images have to be transmitted with the same quality from over 10 Astronomical Units distance. Storage space, bandwidth of transfer, power requirements, and many other things come into play before deciding upon camera resolution.
From the question description:
Are we to believe that nasa spends years and billions on planet exploration probes only to equip them with crappie, low res cameras and no video?
No, you just haven’t done your research quite well.