Why is "Samson had ten men's strength" non-idiomatic?

When the possessive apostrophe is used, the word or phrase before it is usually a unit which you can quantify relatively concretely and easily. For example:

A week's work implies it takes around 35 to 40 hours, which depends on where you live, to complete the work. 10 hours' work works in the same way. You can quantify approximately how much you can produce/write/analyze, etc. in a week based on your own experience and get some idea of how much this work would be. Here, we assume the worker is a run-of-the-mill worker/writer/analyst and we don't emphasize how much it takes.

A week's notice implies you need to give a notice a week prior to an action such as resignation letter or contractually mandatory notice, etc. a notice of a week is never wrong, but doesn't sound as idiomatic as a week's notice.

The same logic applies to several nights' stubble. You know how long mustache or beard grows a day based on your experience. Of course, it can be different depending on people's age or hormone level, but the difference is negligible.

However, the strength of ten men is different. You can't quantify 10 men's strength as objectively and easily as 10 hours' work. It's more abstract than concrete as each man has different strength. Also, the purpose of saying he has the strength of ten men is not to quantify his strength approximately, but to emphasize he is very strong. It sounds more like hyperbole with the strength of 10 men's strength combined which is almost impossible to have in the real world.

Samson was said to be so strong that he could uplift two mountains and rub them together like two clods of earth... [Wikipedia article on Samson]

I don't think it represents the strength of just 10 men.

However,

He's got the strength of an ox, never He's got an ox's strength.

I think it depends. If you compare strength of a giant and giant's strength, the Ngram Viewer seems to suggest almost equal number of results.

I think it all depends on how idiomatic the phrase sounds.

In this case, I don't believe this is so much a matter of indicating quantity as it is possession. The strength "belongs" to the ten men. I read the apostrophe as being possessive. For example, "ten men's wives".

At the same time, "ten men's strength" doesn't read as well to me as "strength of ten men" even though I much prefer direct language over the indirect language used in "strength of ten men".