The issue is not just having most of your offense generated from your backcourt. If you just happen to have great backcourt players who usually generate most of the offense simply because they are so good, but you do have real offense elsewhere when needed, that's not a problem. The issue is having questionable backcourt defense and been too reliable on your backcourt for scoring. You become vulnerable on the defensive end, and more susceptible to being schemed against on the offensive end - particularly when defenses tighten up later in the playoffs and teams need legit offensive options at the other 3 positions.
Lillard and McCollum are a great offensive backcourt. They also gave up 110.9 PPP last year when on the floor together. Portland tried to compensate for their poor defense, and they did that by doing exactly what people are saying we should do here: "surround them with strong defenders on the wing." Well, that's exactly how you end up starting guys like Mo Harkless and Al-Farouq Aminu at the forward positions. Their defense is essential because of Portland's weakness in the backcourt, but they're basically like having two pseudo-Tristan Thompsons on the floor at the other end. You're playing 3 on 5 to some extent.
I'm not going to bitch about the draft pick because of BPA and all that. But I think trying to pound our two square pegs into one round hole as a long-term backcourt is a bad strategy.
One of those guys needs to be moved before next season.
I just do not buy your last point... I also believe Portland exhibited poor team-building strategies the summer after the Cavs won the title, and that has stuck them with bad, unmovable contracts. With all of that said, had Nurkic been healthy, Portland may have been able to beat a KD-less Warriors. And, even if not, they've made the playoffs every year and just got beat in a conference finals. It is not like those are bad outcomes.
Houston has been dependent on its backcourt for over 75% of its offense over the past two years. They also came closest to beating beating the healthy Warriors.
I get your point... if neither Garland or Sexton develop into net-neutral defenders, it becomes exceedingly difficult to win a title. I would also posit that having two offensively-dominant guards poses an advantage against teams with one poor defensive guard. Being able to target an opponent's weakest defender is valuable. This leads me to my final point...
Saying we need to trade one of them before next season, no matter what, is short-sighted and based on an idea that we need to have a competitive team sooner than later. In reality, if the two look good offensively, let them continue to play together, build value, and when an opportunity to transform the team emerges, then you trade that player (OKC with Oladipo, Toronto with DeRozan, etc.).
Now, if it starts looking like a Dion+Kyrie pairing, then I 100% agree, the Cavs have to move one sooner than later. I
think - based on your posts - you believe that is the most likely case. That's fair, and if you're correct, then we have made a grave mistake.
I just hold the opinion that Garland has shown potential, Sexton
obviously has shown potential, and we should at least see what they look like together this season before demanding trades.