Interesting... The same process you describe is what the SEO does to beat the Google algo. If there was a program that did this work for us life would be easier
There is no great difficulty to make such a program... the problem is that you need to test a change before applying or discharding it, and you can not get an immediate answer: depending on the change, you can even have to wait a month. Doing the work manually, you can make the changes more strategically and get more accuracy in less time.
If Google is using learning algos, then in a near future there won't be difference between SEOs and web-designers: google algo will improve systematically and the only SEOing possible will be to do good webpages... isn't this the goal of any browser? Good work, G! ;) I'm not worried because I work on improving the pages when I try to SEO them.