I would turn it round in this case and this would fit your context IMO

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Note added at 2 hrs (2018-11-07 00:05:54 GMT)
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if you would like to be more adventurous, you might go with "the product becomes subservient to the service" but I admit it's maybe going a bit to far out...

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Note added at 2 hrs (2018-11-07 00:06:57 GMT)
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should read "too far out"

First, it is much more idiomatic, in my opinion, to express this in the plural in English. This applies in many cases where a general statement is made about a class of person or thing: "los derechos de la mujer" would be "women's rights" or "the rights of women", not "(the) woman's rights" or "the rights of the woman". You could just about get away with "the product" and "the service", but it is still more natural in the plural. Besides, we really want to maintain the terms "goods" and "services", and there's always a problem with "goods" in the singular: "a good" is unusual.

Second, I don't think any of the usual literal dictionary translations of "a disposición de" — at the disposal of, available to, accessible to, used by — really works here. The gist of the sentence, as I read it, is that goods are secondary to services, they are "in the service of" services (but you can't say that because of the repetition): a means to an end. I think "subsidiary to" would express the idea of "a disposición de" here, because it combines what I see as the two key ideas:

"subsidiary
adj,
1. Serving to assist or supplement; auxiliary.
2. Secondary in importance; subordinate"
https://www.thefreedictionary.com/subsidiary

My stab at it

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Note added at 16 hrs (2018-11-07 13:51:55 GMT)
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I.e. The service predominates the product!