How did the meaning of "consultant" shift from asker to askee?

Reading a different question about the opposite of the word consultant made we wonder why the word shifted semantically from the asker to the person who answers?

From Etymonline:

consultant (n.) 1690s, "person who consults an oracle," from consult + -ant. In medicine, "physician called in by the attending physician to give consultation in a case," by 1872 (perhaps from French, where it was in use by 1867); general meaning "one qualified to give professional advice" is first attested 1893 in a Sherlock Holmes story. Related: Consultancy (1955).

The structure of the word suggests one who consults (others).

Consult means to ask or refer to. e.g. Consult the experts.

-ant (and its sister -ent) give the meaning of taking action or agency.

Attendants attend others. Commandants command others. Regents rule others. Dependents depend on others. Etc.

How did consultant shift from the person asking to the person asked?

I think Etymonline description is quite clear. The fact that originally the term was applied to “person who consults an oracle“ may create confusion.

Those who “consulted an oracle” were privileged people who had access to oracles whose opinions were often requested by ordinary people who wanted to know the views and suggestions of oracles. In that sense the “consultant” was still someone people relied on to have their advice.

In modern times, oracles disappeared but consultants remained.

In medicine, "physician called in by the attending physician to give consultation in a case," by 1872