Edibles are very consistent, at least today they are. The problem with them is that people are stupid and don't know how to find the right dose responsibly. They take a gummy, it tastes pretty good, and then after 15 or 20 minutes they don't feel anything so they take another, because yum, it tastes like candy so why not. Then it starts to kick in after 30 or 40 minutes and it's double the dose so they feel nauseated and sick.
The best way to gauge the effects of an edible dose is to take the edible on an empty stomach, wait about 20 minutes, then eat a meal, and do not take a second dose. After eating your metabolism will get that dose into your blood stream right quick and before you're done with the meal you will definitely be feeling the full effect if you took enough. And if you don't feel much, then the dose is too low. Try again tomorrow. Don't double up the dose in the same sitting, because then you're really not getting an accurate result. Take maybe 1/3 more the next day, try again. If it's still not enough then the next day try a little more. When you find the right dose, then stick to it.
That being said, the other side of this (in a pre-legalized world) was that the plants you grew on your own tended to be within a certain potency range, which meant 1 puff roughly equaled another — as opposed to baked goods, where butter could end up spread throughout inconsistently. There’s also the swifter intake-to-feedback loop when smoking/vaping, which made “taking too much” easier to see coming and avoid. Thus my old fashioned POV.
But you're right, it's way easier to not "overdose" with inhaled THC than it is with edibles. People just need to approach the two methods differently. Inhaling is instant gratification, where as eating is delayed gratification. Not everyone is capable of delaying gratification because so many people are impatient and impulsive. Edibles are still vastly superior in terms of healthiness so long as they aren't just 95% sugar and 5% THC.
Personally, these days I use "Protabs" which contain 0 sugar, just THC and a binder (probably corn starch) and the high is extremely clean and clear and completely guilt-free. And the dosage is very reliable and repeatable. There's no guessing involved now that I know my tolerance.
I get what you’re saying - but this is not practically true. Weed that contains 35% THC has a lot to do with the conditions it’s grown in which affects a lot of the other physical qualities of the weed. Smell, color, size of nug, density, humidity all are very correlated with potency.
Density is just a measure of humidity in practice and thus pick date.
Alternate take, dispensaries have enabled many people I know to get a reliable product that acts the same each time they buy it and use it, and let them dial in exactly what strain and quantity and method of ingestion works best for them. Before the commercialization one never had the diversity and reliability of product they have now.
Contrast that to the before times where people, as you put it, bought whatever the dealer was selling.