It’s perfectly fine not to provide these properties. Schema.org doesn’t require any property.
If Google’s Structured Data Testing Tool says that certain properties are missing, what it really means is:
"If you don’t provide these properties, we won’t show the corresponding Rich Snippet or Knowledge Graph feature in Google Search"
There’s no need to get rid of your structured data just because Google (as one of many consumers) currently doesn’t do something with it. It can be useful for other consumers, and Google may change/introduce features in the future that work with your current set of properties.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…