Under your simple scale you would exclude Nelson Mandela, the Dalai Lama, and Stephen Hawking, respectively. I think they've all been supremely wasteful 'consumers of resources.'
Exceptions all. The point of any laws is not to catch the exceptions, but to state the rule for the average.
There's no way a standard policy is going to somehow separate the Stephen Hawkings from the general population before they have actually accomplished anything of note.
So your policy can either be cautious, or it can be over liberal.
The steven hawking outliers can apply under the O-1 visa type schemes, which he would definitely pass. A points scheme doesn't have to be the only scheme.
And you think of the millions of people wanting to get in here they're all world-renowned physicists or spiritual leaders? We would long run out of money supporting the hordes of cancer-stricken dirt farmers clamoring to get in here before the next Stephen Hawking shows up.
Ask Australia? But at a very basic level:
* Criminal background -> sorry
* No high school-equivalent education -> sorry
* Crippling, expensive disease -> sorry
Those are just three basic things that let you know straight away that this person has little chance to do anything but consume resources.