Article about doing a PhD by prominent mathematician or computer scientist
Here are some sources I have found that speak to the topic of not getting a PhD. 

Perhaps this document is the one you are looking for? Both the authors are mathematicians with PhDs. I would not say they are necessarily prominent, but they are established. 

http://www.maths.manchester.ac.uk/media/eps/schoolofmathematics/study/guide_2011.pdf



This is a short article reposted by a professor at Stanford University.

https://tomprof.stanford.edu/posting/545



Here are three other online articles about the topic.

https://medium.economist.com/why-doing-a-phd-is-often-a-waste-of-time-349206f9addb

https://www.theguardian.com/commentisfree/2018/aug/15/should-do-phd-you-asked-autocomplete-questions

https://www.cbsnews.com/news/12-reasons-not-to-get-a-phd/



I will add my own brief commentary here. Obtaining a PhD has never hurt me financially. I have a well paying full-time job that requires a PhD. (Now should the job require a PhD is a different story). There are many, many, many jobs in my field (statistics) that prefer a PhD. I have never regretted obtaining a PhD.