Why are more fossils not found?

Answer 1

Asking why there are more animal fossils presupposes that there are more animal fossils than plant fossils. This is not the necessarily case. Plant fossils are actually much more common than animal fossils. If you consider the distribution of biomass in modern ecosystems, it is clear that plants are the dominant kingdom (e.g if you walk into a rainforest, you see hundreds of trees, but few large animals). This distribution is a necessity for any functioning ecosystem because the plants are primary producers (other species need them for survival).

Lignite, a low grade coal, is composed entirely of semi-compacted plant fossils. It is so common that it is often burned for use as fuel.

This being said, plants also decay faster than animals given the same initial conditions (they do not typically have hard parts like bones), so the percentage of plants that are fossilized should be less than the percentage of macroscopic animals. Since plants so greatly outnumber animals, however, this does not make fossil animals more common.

Addendum:

It matters too whether one is discussing microfossils or fossils large enough to see or whole fossils or merely a fossilized leaf. See related questions.
Plants have softer bodys parts than animals

Answer 2

This is due to decay, the plants take about 20mil years to decay, this is how we get oil. A plant would be lucky to survive the harsh weather millions of years ago, and the animals and many other obsticles, its chances of being observed millions of years later are very slim. Thus there are very few fossils.

Answer 3

More fossils are not found because they are old and people have found most of them already. More fossils will be found later on in life because then more will be formed.