People need to make sure they can handle what they choose. I often see working people (doctors, lawyers, and other simple professions) who come both to hashkoma minyan and at 9pm to learn at kollel, and also there are people who live holy lives of learning and teaching and whose heads are worrying about where they can earn money to support their families. I don’t know percentages, but one should evaluate his own (and family) tolerances and be realistic in their lifestyle choices.
In theory, in modern world, one can spend 4 years to learn a good profession and then work 1 day a week (or 2 hours a day, if you prefer) and have a great learning life. I never met anyone following such an obviously correct way. R Lebowitz says that one YU student suggested a similar idea – be a lawyer full time until 40 and then retire, and Rav advised against that.