That sounds ideal but oftentimes, intentionally or not, that isn't the expectation communicated. And in some cases I have seen take home coding exercises that are literally projects big enough for weeks of work. That particular small startup had copied their take home exam from a bigger company. They told me "work as far as I can," but it is intimidating and accomplishing a reasonable amount in say half a day still would feel like I had barely scratched the surface of the work they "suggested" I do "as much of as I feel like." It made me feel like an inadequate candidate by feeling like I can't possibly put enough of a dent in that task for it to be meaningful.

Oh and by the way the people asking me for that work were significantly more junior than me. I politely passed on the company and even beginning the take home test.

I have also had a company give me an API to build with sparse instructions. I did my best, I probably should have asked them more questions. I got no response. I followed up weeks later to see if there was more I could do with the coding exam or if I misunderstood it somehow. They didn't have anything else to say about the coding exam but they did invite me in for an in person interview. They then ghosted me and my further follow ups about the status of the hiring process.

The thing about the hiring issues in the industry is they aren't as simple as the solution you offered up. They are systemic and it doesn't feel like anyone is even trying to improve them. And that the changes that do happen are equally but differently absurd in their expectations as the mistakes of the past.