I agree with the lineups you see happening, but am horrified by them rather than comforted.
Maybe you should start watching Laker or Miami games then.
Seriously, there is NO team that has "legit backups" at every single position.
It is an absurd strawman (something you are very familiar with) to claim as a negative the failure of the Blazers to achieve something no team does.
As for the starters and backups, there is no such thing on most teams. Starters rotate out and subs come in. Except in very limited minutes and blowouts there will always be one and usually two starters on the floor at all times.
The Blazers have a team with multiple players that can cover more than one position. Subsitions can occur throughout the game. No "platoons".
Miller can play 1 or 2.
Roy can play 1, 2 or 3.
Batum can play 2, 3 or 4.
LA can play 4, or 5.
Oden is a pure 5.
Bayless can play 1 or 2.
Matthews can play 2 or 3.
Cunningham can play 3 or 4.
Camby can play 4 or 5.
Pryz is a pure 5.
If all healthy Nate can play a lot of big lineups that should be hard for most teams to handle. If injuries or matchups dictate Nate has the ability (and long-time shown preference) for playing lots of small-ball.
No "legit" backup PG? Could be a problem if Miller gets hurt, something that has never happened before. Otherwise, Bayless is trying to become a "legit" backup PG. If he fails this year, it may limit his NBA prospects and he knows it. Regardless, he fills in nicely as a guard that defends the PG and plays SG on offense next to Roy. And charges into the paint when he is out there without Miller or Roy. Our PG minutes on offense are all well coverered by Miller, Bayless and Roy.
SG you claim is our "best" position, seems no better or worse to me. If Roy goes out we have a challenge to make it work for any extended period, especially on the offensive end. But with the excellent size our team now posseses, all of our rotation guards can help defend the 2 spot, and the versitile Batum can take minutes there as well.
SF if Batum gets hurt I think we are well covered with Matthews, Roy and Cunningham able to take over the rotation there.
PF you claim is a weakness, yet LaMarcus play the most minutes on the team, Camby is more a 4 than a 5, and at this point in his career becomes one of the better backup Power Forwards in the NBA. How on earth that is a "weakness" escapes my feeble brain.
Center, we have 3 solid defensive rebounding and injury-prone centers (and LaMarcus can play backup center better than most NBA backup C's) and somehow you turn the caution of 3 legit 7 footers into a disaster.
There is nothing any of us can do about Oden's health. Or Pryz. Or anybody else. We can't trade Oden for Howard. We could only trade him for a small or for another injury prone big or a far less talented one.
Me, considering what the team had to work with, I am happy they traded for Camby and have locked up the versitile LaMarcus, giving us options to man the paint.
If healthy, I see this roster as a dark-horse contender. I don't expect complete health, so, I don't think this is the year the Blazers make a run. In which case, why are you fretting so much about lack of "legit" backups to this or that spot?