Why isn't the preposition "from" used to form self-sufficient phrasal verbs?

Some verbs usually take objects. Some take two. Others take different types of complement. Although most verbs can take more than one pattern, there are some which are nearly always transitive. They usually have to take an object.

The same is true of the prepositions which we find in so-called phrasal verbs. What the Original Poster has noticed is that from, like the prepositions to and at, is nearly always transitive. These prepositions must have a complement. For this reason they don't appear in 'intransitive phrasal verbs' either.

We can contrast these with other prepositions like back or away, which are intransitive and don't take noun phrase complements at all.

However, notice that because from, to and at, for example, don't take noun phrase complements, does not mean that they are always self-sufficient. Many intransitive verbs take other types of complement apart from noun phrases. For example, they may take preposition phrases: Look at me!. Or they might take verb phrases: I want to go! In exactly this way, many prepositions can take other types of phrase as a complement. This includes, for example, the preposition from: He came from out west or He jumped from behind the curtain.

^{This analysis is the one that you will find in the majority of modern reference grammars, such as Oxford Modern English Grammar, by Bas Aarts (2011). Traditional grammar regards intransitive prepositions as adverbs.}

Observations:

The Original Poster asks why, for example, from nearly always has a noun phrase complement. One theory is that from, at and to introduce points, not directions or areas. Instransitive prepositions usually in themselves represent areas, spaces or directions.

A second reason is that the other intransitive types of preposition that you can use without a noun phrase are deictic. So for example, if I say it went up, we know from the discourse that it went up from where it was, or from the ground. If we say He went away everyone knows we mean away from here or away from where we've just been talking about. If we say she walked out, we understand she walked out of the room, or out of the house or out of the meeting. However, the object of from normally indicates something that we can't readily identify by reference to here or now, or the ground or the sky. It most often doesn't have a readily identifiable anchor, or starting point. That place is rarely here, or where we've just been talking about (although it can be).