Usage of "let" with an inanimate subject

Question

Can anyone help me and explain if the usage of "let" together with "these things" is grammatically correct in the following passage?

We have created many useful things such as airplanes, trains, computers, medicines, as well as institutions such as schools, universities, hospitals and banks. Without them the modern world would not exist. These things let us travel far and wide, gather information quickly, educate ourselves, and treat diseases.

In my grammar textbook, they say you cannot use "let" with an inanimate subject. Personally, I didn't find the sentence strange when reading, but it should be wrong and corrected according to the grammar book. This sentence sounds OK to me; is that because the subject is a pronoun, "these things," although "thing" is still inanimate.

And if that is the case, how about this sentence below?

Airplanes and trains let us travel far and wide.

This does not sound too awkward either, but to be grammatically correct, does the sentence below look better?

Airplanes and trains enable/allow us to travel far and wide.

Please anyone help me find out if you cannot really use "let" with an inanimate subject. Thanks!!

Answer 1

There is absolutely no reason why let should not be used with an inanimate subject — just as enable or allow can be. Let is a synonym, after all; if an inanimate object can allow something, then it can let it happen, too.

There may be an issue where let is used in its archaic/obsolescent sense of hinder (the tennis call of "Let!" is used when the ball is hindered in its passage by hitting the net; there is also the fixed phrase "let and hindrance"). In this case, let is very rarely used in an active form; if it's only used in the passive voice, it doesn't have a subject at all, inanimate or not.