Ask HN: Why don't smaller US companies sponsor E-3 visas?

I've noticed a lot of smaller US companies will not even consider engineering applicants that need E-3 visa[1] sponsorship. Does anyone know why this is the case? I'm talking about senior software engineering roles or above.

Afaik, the employer needs to apply for Labor Condition Application [2] and then help the employee with applying for the visa. I estimate roughly ~10k in costs and ~4 week turn around.

[1] - https://en.wikipedia.org/wiki/E-3_visa

[2] - https://en.wikipedia.org/wiki/Labor_Condition_Application#Attestations