They have cheap gas only because they are so under-utilized. You cannot count on gas being worthless because spam isn’t actually free, at least not for the execution layer.
Core devs know each other but they aren’t exactly friends and they don’t agree on priorities. Their common interest is in not wasting their own time.
It is easy to believe conspiracy theories about your opponents. Many Ethereum developers (including myself) are ex-Consensys because it was a huge company. This doesn’t mean they have a huge interest in advancing Consensys’ interests, even if they have stock. This is because Consensys is internally decentralized to the extent that there is little coordination or contact between projects. Consensys is simply too toxic and unfocused to have members of one team advancing another team’s interests, never mind spies infiltrating core development. lightclient is advancing 3074 because he believes it is good, not because he is a puppet for his former employer.