Could a historian be neglected because of bias?

Yes, absolutely.

History contains many examples where scholars were initially ignored, marginalized, or dismissed because their ideas challenged dominant assumptions.

Possible reasons include:

political pressures,

intellectual fashions,

institutional power,

language barriers,

national traditions,

disciplinary boundaries.

Examples often discussed include:

Ignaz Semmelweis in medicine,

some early anti-colonial historians,

scholars writing outside dominant academic languages.

So my point is valid:

Lack of citations does not automatically prove an idea is wrong.

However, the reverse is also true:

Lack of citations does not automatically prove an idea is being suppressed.

Both possibilities exist.

That is why historians usually ask:

What evidence supports the claim itself?

rather than deciding solely from the popularity or unpopularity of the idea.