Tense in subjunctive sentence

The divorce won’t affect the money that has already been given to the foundation trust, but the couple may devote less money to it over time than they would have if they had stayed together.

The tail end of the sentence, from a news article, after than describes a contrary-to-fact situation in the past tense (not about the verb form) as the divorce is already set in motion. The author apparently sees this section as a past event, a perspective that I cannot wrap my head around.

But I wonder whether it is possible to describe the situation in the present tense--they would if they stayed together. Indeed, I feel the present tense is more appropriate in this subjunctive sentence.

Could you please explain why the past tense is applied here?

Solution 1:

Sorting Things Out

The fact that the clause in question is embedded in a comparative construction is a red herring. So let's get that out of the way by creating a new sentence:

(1) They would have devoted more money to it over time if they had stayed together.

Also, it's another red herring to argue over whether to call this sentence "subjunctive" or not. So let's not discuss the terminology but only focus on the verb forms in bold.

Now, the question the OP is asking is how in context--apparently, in the context of the divorce of Bill Gates--does (1) compare to (2)?

(2) They would devote more money to it over time if they stayed together.

I don't quite understand why the OP would call the verb forms in (1) "the past tense" or the verb forms in (2) "the present tense". If anything, had stayed in (1) is not the past tense but the past perfect tense, and both would and stayed in (2) are in their past tense forms.

So I'm afraid that just as the terminology "subjunctive" is a red herring, so are the terminologies "the present tense" and "the past tense" as used by the OP. So let's ignore the terminologies "the present/past tense" as well and simply focus on the verb forms without calling them anything, because those terminologies don't help us answer the question.

Questions

The OP seems to suggest that it is possible to describe the situation of the Gates divorce in (2). In fact, the OP seems to think that (2) is better than (1). And the OP asks if (1) is even a valid construction in context.

Short Answers

I agree with the OP that (2) is also possible in context. But I believe that (1) is the better construction in context because the counterfactual situation is more vividly conveyed in (1) than in (2).

Long Answers

The divorce is being processed, so the "staying together" stopped at some point in the past. Although (2) can convey a counterfactual situation that covers both the present and the future, it cannot describe the past when the divorce process started. Thus, (2) is somewhat limited in describing the counterfactual situation in its entirety.

Now, turning to (1), they had stayed together describes a past counterfactual situation starting from the point where the "staying together" was stopped by the divorce process. But "devoting more money to it over time" has only to be subsequent to "staying together" and does not have to be limited to the past but certainly can include the future.

The verb form "would have + past participle" usually describes a past event, but is not limited to describing a past event, unlike the verb form "had + past participle", which is limited to describing a past event. Assuming that the verb form "would have + past participle" always describes a past event can sometimes lead to confusion.