sentence structure and sequence of tense

It's a complicated situation, with English seeming to be in flux. Here is my idea about one thing that is going on. Sometimes, what appears to be a complement sentence functions as the main assertion, and what appears to be the main clause gives the grounds for that assertion. When this is so, the functional main assertion may have a present tense verb, while the grounds for asserting it may have a past tense verb. And so we wind up with a violation of the sequence of tenses rule.

Let's take Peter Shor's example: "Yesterday, I learned that our company is planning to lay off our entire division." This asserts "Our company is planning to lay off our entire division", giving as grounds "Yesterday, I learned". If expressed like this, "Our company is planning to lay off our entire division, as I learned yesterday", it would be unproblematic. But now, for some of us, there is the option of expressing the "I learned yesterday" part as the main clause.

An odd construction with tags was noticed by Jerry Morgan: "I believe the Yankees lost the pennant, didn't they?" A tag question, like "didn't they", ordinarily goes with the main clause and not with a subordinate clause: "Horace doubts that the earth is flat, doesn't he? / *isn't it?". So, in Morgan's example, the apparent complement sentence, "the Yankees lost the pennant", is behaving grammatically as though it were the main clause.

Let's add a tag to Shor's example, and see what happens. "I learned yesterday that our company is planning to lay off our entire division, (i) didn't I? / (ii) isn't it?" Which tag is grammatical? I say, it's (ii), and if so, this is evidence that the apparent complement "our company is planning to lay off our entire division" is acting like a main, asserted, clause.

So, in answer to your question, I think it is easier to find examples of reported speech that violate the sequence of tenses rule, because we often cite what someone said previously as grounds for our own current opinion, but we can also find other cases where the grounds for our assertion are given in what looks like the main clause, but functionally is more like an adverbial.