Of course, it's not real demarchy because politicians may still choose to ignore opinion polls (and often do).
I think the question is not really clear. At first glance it appears to depend on how you define the term demarchy. "Can such a form of government be called demarchy?".
Hayek first used the term demarchy for something completely unrelated. Later Burnheim in Is democracy possible? uses it when he proposes a form of government that includes the dissolution of the state and sortition, among other things. Some now use it to refer to any form of government that strongly relies on sortition. This is the use that wikipedia makes of the term, in the article you link. In all cases the answer would be: no, I do not believe the presence of opinion polls can be ground of calling a political system a demarchy. (I would avoid the term entirely, as it is ambiguous, and not an accepted term among scholars, who never use it, I recommend to just talk about sortition, to avoid confusion).
What perhaps you really meant to ask is:
What is the relationship between opinion polls and other uses of sortition in politics?
What opinion polls have in common with other forms of sortition is that they somewhat accurately expresses the will and opinion of the people.
As you correctly state however, opinion polls are non binding. Politicians routinely ignore them when it so pleases them. In contrast, in many of the past and proposed uses of sortition allotted bodies can make binding decisions. This is not always the case, for example it has most often not be the case for deliberative opinion polls.
Furthermore, when talking about sortition usually it is assumed that the selected citizen will have a chance to meet in person, deliberate and often go through an information phase where they get a chance to meet with expert, before making their decision. This way they can make a more informed decision.