Unfortunately while that sounds good in theory, it is not always applied in practice. Not to mention that studios, producers, etc are worried about their own profits, and not what their clients wish to attain. You would not believe how often things are cut or shortchanged simply because they want to save money or are too cheap to spend any more, regardless of the fact that they're fully aware it'll adversely affect their product.
Here's an example again from my own experience:
Season 13 of Mayday - Art Department of 9 personnel, budget almost unlimited - You need to get what? Sure, here's some money, spend a little extra to get the best of the best as well.
Season 14 - Art Department cut to 5 people, 1 of which is a daily that would come once a week for the big shoot days. Budget limited.
Season 15 - Oh you guys managed to do it last season with 5 people, and a limited budget? Let's cut that to 3 people, 1 daily, and half the budget from last season.
Season 16 - Oh yeah, the show somewhat suffered and looked limited/cheesy in certain areas that the seasons prior it would not, but ratings were still strong and you had to work longer hours to achieve what we wanted, but you somehow did it, even if just barely. Let's see if we can cut the department to 2 people, 1 daily, and you can get back to us. Oh and your budget? Non existent. Recycle old **** from previous seasons. PS, you're now working 6 days a week when we aren't shooting, 7 when we are, so you'll get 1 day off now every 3 weeks. You want a 10-12 hour day? GTFO - You're working 16 minimum. Oh and you're also not getting overtime or paid hourly, you get your flat weekly or daily rate, which we are also now looking at cutting. Wanna complain? Go ahead, but we're one of the biggest producers of media in the entire country, and we guarantee that while you'll work in the industry, it will never be for us again. And we'll make sure everyone we know has your name (which unfortunately, as big as the industry in Canada/Toronto is, EVERYONE knows someone that you do - I have never worked on a single show or film that I did not know at least 2 people from prior jobs, and at least another 2 or 3 that knew people that I did - so they can and will screw you).
Look up Hollywood Accounting if you want to see exactly what I am talking about for just another example of many ways studios screw over their employees, even the literal face of their product. It's common practice. So no, while most of the time Jon C would be correct in the sense of using someone's likeness, that is not always the case. It's entirely plausible that Cushing's family got zero from this film.