A quick search shows a company here will produce 5000 DVDs for £0.27 each. That's with full-colour printing, but no packaging.

A 25% tariff would add $0.08 to to each disk. That hardly seems likely to affect the decision whether to publish with a DVD or digital-only.

I assume manufacturing prices in Mexico are similar (mostly equipment and materials cost, not much labour).

The overhead of compliance can be high for people not experienced with compliance. You can either paying the dumb tax directly or paying for expertise.

But even if the line item cost of expertise doesn't add much to overall costs, there's still the dumb tax for finding expertise.

And the inevitable concerns and hiccups that come from finding new suppliers.

Basically, risk and uncertainty and process change have high business costs...it might not be worth betting the business on getting all the details right.

The disc itself costs practically nothing so a workaround could be found.

Its more likely they just want to end physical media so they don't have to pretend you own anything anymore.