His supposition is based on the diversity and availability of materials, additional process requirements, and cost versus traditional manufacturing.
And he would be right if the traditional manufacturing paradigm is preserved.
Which it wont.
With the proliferation of such printers, product design, process, and material specifications will change to accommodate and compete, if not replace much old school assembly-line stuff.
I’m not talking about machines like the replicators from Star Trek. Oh, wait, I am. And I’ll take the bet that in 25 years everyday people WILL churn out plasticware for picnics instead of going to the store.
And a host of unimaginable products otherwise unavailable, as ubiquitous and available as phone apps are today.