Liaison is a very robust phenomenon in French. As far as I know, there is no variant of French that does not have liaisons. Liaisons exist and follow a pattern of mandatory/optional/forbidden in Europe, Québec, subsaharan Africa... Even many French-based creole languages incorporate liaisons, sometimes in non-standard way (e.g. a noun might incorporate an n or z prefix that migrated from the French article un/des).
Very young children might get liaisons wrong. A typical example is that they might learn a noun that starts with a vowel as if it had an extra n or z prefix, because they heard it with an article. For example a child might say « *des nenfants » *[de.nɑ̃.fɑ̃] because they heard « un enfant » [œ̃.nɑ̃.fɑ̃] and generalized it as being the noun « *nenfant », or conversely « *un zenfant » *[œ̃.zɑ̃.fɑ̃] from an invalid generalization « des enfants ». And a child might end up saying « *un / enfant » *[œ̃.ɑ̃.fɑ̃], because they don't master liaisons and they don't know when to do it. But the phenomenon of liaisons is present in early speech. Studies 1 2 tend to show that mandatory liaisons tend to be mostly acquired at kindergarden age.
For certain types of optional liaisons, some speakers might consider that particular type mandatory, or some speakers might consider that particular type forbidden, while other speakers could make it or not depending on the circumstances. But there is a core of liaisons that is mandatory for all speakers.
The association between a subject pronoun and the following verb is very strong in French, to the extent that linguists often analyze the subject+verb in colloquial spoken French as a distinct lexical element in some cases. For example, « je sais » (I know), formally pronounced [ʒə.sɛ], is often contracted into [ʃɛ], which could be written « chais » (« Je ne sais pas » ≈ “I do not know”, « Chais pas » ≈ “I dunno”). This is not a liaison, but it illustrates the more general point that the pronunciation of the subject pronoun is not independent of the verb. Coming back to liaisons, in colloquial spoken French, some subject pronouns can be abbreviated when they are followed by a verb that starts with a vowel sound to the point that only the liaison remains : « on » → [n], « vous » → [z], « ils » → [z]. For example, « vous avez » [vu.z‿a.ve] can be colloquially pronounced « z'avez » [z(‿)a.ve]. In a sentence: « N'avez-vous pas honte ? » (formal: “Are you not ashamed?”) = « Vous avez pas honte ? » (informal, neutral or emphasized) = « Z'avez pas honte ? » (informal, not emphasized).
The only circumstance in which I can imagine a native French speaker pronouncing « vous avez » as *[vu.a.ve] is if they are simulating a foreign speaker.
