I am not sure if this is really "effective altruism". When I decided to leave a high paying job to start an education startup in order to pursue my passion to make a change through education, I got similar advice. I was told it would be more "effective" to keep my job and donate the money to education related charities instead. But I realized that as an software engineer, my skills could prove much more impactful, and directly so than the relatively meagre money I could donate. As they say money is cheap. I felt, and I still feel I could amplify my impact by using my skills rather than just throwing money at the problem.
Second, I wanted to be more aware and involved in the issues I wanted to contribute to, which I couldn't do unless I dove in. There are a lot of good organization out there that are making great impact, but there are equal number of "bad" ones that are perhaps having a negative impact or are not aligned to ones values. GiveWell and CharityNavigator can only go so far.
I think both you and the article are in-line with effective altruism (the movement). The crux of EA is objectively and dispassionately deciding what causes do the most good with your scarce resources (time & money) and deciding how to best support them. Reasonable people will disagree on whether working in the industry or donating profits from a higher-paying industry will work better for you. Education isn't a popular EA cause but whether it is or isn't optimal depends on the change you think your start-up will have contrasted against what impact you could have elsewhere.
Check out https://80000hours.org for a way more in-depth exploration of the different career-related EA strategies.
The relative impact of your money vs your time depends in part on your income, you skill-set, and the causes you would choose.
A person with a high income but few relevant skills would probably have the greatest impact by donating money. For example, a trader interested in preventing disease might not have any skills in developing or delivering vaccines. But that trader might have a substantial amount of money to donate to organizations that do have those skills.
On the other hand, a software engineer with a modest income might find a very effective nonprofit that could do much more if only it had access to software development talent. For that engineer, donating time might achieve much more than donating money.
Second, I wanted to be more aware and involved in the issues I wanted to contribute to, which I couldn't do unless I dove in. There are a lot of good organization out there that are making great impact, but there are equal number of "bad" ones that are perhaps having a negative impact or are not aligned to ones values. GiveWell and CharityNavigator can only go so far.