As far as I know, the major difference between insulin types is not their performance, but how long they take to act, when they peak and for how long they have an effect. Some types of insulin, like glargine (as in Lantus®) can be more convenient due to their long-acting response that lasts for an entire day.
I suppose off-patent insulin could be produced with some degree of inconvenience to the consumer because they might have to take more doses per day, but they should work nonetheless.
Long acting insulin is exactly what this entire debate has always been about. Generic standard insulin has been cheap at walmart forever. They even sell cheap rapid acting ReliOn.
People want long acting insulin cheap. (short-, intermediate-, rapid-, and long-acting, ultra-long-acting (42h) insulin are the main categories.) Long acting insulin was the product that had a price jump at the end of 2017.
I am pretty sympathetic to the non long acting stuff not being good enough. Expecting people to monitor hour after hour, and only calling it an inconvenience really downplays how tedious it is to stay alive.
T1D patients use both types if they are self-injecting. The long acting covers your basal rate (baseline) and the fast acting covers carbs you eat.
Or if you have a pod or pump then you can use only the rapid acting and the software will drip it slowly to cover your basal need over the 24h.
Trying to use just the fast acting with self-injections doesn’t work because you go high overnight while you’re sleeping, and even during the day you would have to be injecting every 3 hours to keep up. (E.g. when your pump controller dies on vacation and all you have on hand is rapid-acting)
Which would be covered by traditional mixed, short and intermediate insulin, right? The price of Novolin 70/30 (mixed), Novolin R (rapid) and Novolin N (intermediate) insulin have remained flat since 2014. (Short acting and Rapid are two different things, the former being the old kind of insulin that takes 30 minutes, the latter being modern tech that takes minutes.)
It's when you want something better, that lasts longer than Novolin N that price starts to go up. (Novolin N is typically injected underneath the skin (subcutaneously) once or twice per day.)
Obviously, if you have insurance, I would expect you to be being prescribed something better, because that's how the world works. Then you can jump from traditional insulin to rapid and long lasting, and pens.
I suppose off-patent insulin could be produced with some degree of inconvenience to the consumer because they might have to take more doses per day, but they should work nonetheless.