Irrelevant, the apps it's being used for would run fine on a 25yr old machine at 60fps.
You shouldn't need multi-threading to render a few thousand objects and most UI apps of the type Lottie is being used for animate 100 or less at a time.
Note: It's good that Lottie runs faster for its users. My point is only that the entire stack is over engineered and the solutions being used are because the stack is bloated and inefficient
I agree with the general point you're making, but a 1997 computer would not be able to render even just a basic loading spinner at 1170x2532 at 60 FPS. Software rendering would be impossible even with an infinitely fast CPU as it would exceed the bandwidth limit of AGP 1.0, which itself only came out that year. The graphics hardware at the time simply did not support that resolution at any speed.
This is a common problem when people complain about graphics performance and compare to older hardware - we forget how much higher modern screen resolutions are. It's not a smoothly scaling problem either. As often with scaling, you hit problems at particular levels that require a totally new solution to the problem. CPU speeds stagnated whilst screen technologies didn't, hence, complexity.
You shouldn't need multi-threading to render a few thousand objects and most UI apps of the type Lottie is being used for animate 100 or less at a time.
Note: It's good that Lottie runs faster for its users. My point is only that the entire stack is over engineered and the solutions being used are because the stack is bloated and inefficient