There's no guarantee that the same deal would still be on the table after the drug test, especially if it's positive and strengthens the prosecutions case.
It's to expensive to make sure innocent people (as in the government has no actual evidence you committed a crime) aren't going to trial or prison ? There is really no surprise America has the highest level of incarceration in the developed world. Your government gathering legitimate evidence against you before charging you with a crime shouldn't be something that's to expensive to do. It should be the baseline.
This isn't about being in an egalitarian society, the right to counsel is in the sixth amendment but everybody is to busy fussing over the 1st and 2nd I guess they haven't got that far yet. Or quite frankly don't care that the counsel people recive is insufficient because they never see themselves in that position. It's not that the court appointed attorney "might not have time" it's that he didn't. Watch the episode I told you about and you'll understand that if you ever need one they won't have time either.