I think it’s usually explained in the opposite direction (が emphasizes what comes before it, while は emphasizes what comes after it), but I guess it maybe depends on how we’re understanding “emphasis.”
Generally speaking, the “topic” marked by は is something that is mutually known by both the speaker and listener. So, in AはB, the new information (or in questions, the information we’re seeking) is going to be in B, since the purpose of A was only to set up and provide context for the rest of the sentence. One clever way to conceptualize “○は…” in English is, “As for ○, …” This is because even in English, it’ll sound pretty weird to put something your listener doesn’t know about for ○.
Conversely, が marks the “subject” of a sentence. Unlike は, this part of the sentence is quite literally necessary for the sentence to be understandable, despite Japanese often leaving it implied. In English, the “subject” is usually the first word in any sentence we make: “I am Tom,” “She is busy,” “It’s going to be on Saturday,” etc. Anyway, Japanese mainly uses が instead of は when the sentence’s new information is in front of the particle.
You may notice that questions are always framed with が. This is because the new (or sought-after) information belongs in front of it:
- A：だれが来るの？ B：トムが。
は also brings a feeling of contrast with it (it’s often called “contrastive は”), so most compliments will be said with が instead, to avoid implying anything negative. Saying something like 今日のごはんはおいしいです！ to your host family for example would sound like a backhanded compliment, as if other days’ meals weren’t おいしい. For this reason, I think you’ll find nearly all of your example sentences for 好き are framed with が, unless it’s an intentionally contrastive sentence like Xは好きだけど、Yは好きじゃないです。 This sounds something like, “I do like X, but I don’t like Y.”
All that being said, in AはB vs. AがB, both particles are actually “marking” A. It just so happens that sometimes, we’re more interested in hearing what the speaker has to say about B