The $1000 Nikon P1000 has a 24-3000mm 35mm-equivalent lens with a maximum aperture of f/8 at the narrow end. This corresponds to a 539mm focal length.
It uses a 1/2.3" sensor, 6.2mm wide and 4.6mm tall. This is roughly a 4:3 ratio. The resolution of the sensor is 4608x3456, or 15,925,248 pixels.
The largest angular diameter of the planets are, as follows:
Venus - 1'6"
Jupiter - 50.1"
Mars - 25.1"
Saturn - 20.1"
The sensor has a pixel diameter of 1.3 um (micrometers), circle of confusion of 3.33 um, and an airy disk diameter of 10.7 um.
The field of view is equal to 2*arctan(0.5*[dimension]/focal_length), so the width is 0.6591 degrees and the height is 0.489 degrees.
Each pixel is about 0.51" square. Now for how much (horizontal or vertical) space each planet occupies:
Venus - 129 pixels - 167.7 um
Jupiter - 98 pixels - 127.4 um
Mars - 49.2 pixels - 63.96 um
Saturn - 39.4 pixels - 51.22 um
On the extreme end, a $3300 35mm Nikon D850 has a resolution of 8256x5504 - 45,441,024 pixels. Assume it's paired with a $16,300 800mm f/5.6 lens.
The sensor has a pixel diameter of 4.4 um, circle of confusion of 10.9 um, and an airy disk diameter of 7.5 um.
Given the sensor size is 36x24mm, the frame width is 2.578 degrees and height 1.719 degrees. Thus, each pixel is about 1.124" square.
Venus - 58.719 pixels - 258.3636 um
Jupiter - 44.57 pixels - 196.108 um
Mars - 22.33 pixels - 98.252 um
Saturn - 17.88 pixels - 78.672 um
So for the price of a car, you get a sharp, but smaller, image that's less diffraction-limited. I'm pretty sure cheaper telescopes can do a better job.
That was excessive.
Also,
http://www.wolframalpha.com/input/?i=(1.22*(500+nanometers/67+millimeters))(180/pi)
For the P1000, the angular resolution is 2.06", or about 4x the pixel width.