50 years in DC and literally nothing meaningful to show for it except for being a known racist and segregationist. You don't become a career politician unless there's money to be made, especially if you're in for 50 friggen years.
To become a career politician one must win elections, over and over again. He won and kept winning his Senate seat seven times. Obama selected him to be his running mate so, technically he was along with Obama twice elected VP. He was elected President in 2000. All this adds up to ten times that people voted for him, putting him in office over a period of fifty-two years.
His starting Senate salary was $42,500 in 1973. His ending Senate salary was 169,200. As VP he was paid in 2008 $221,100 and in 2016 it grew to $230,700. As President he earns $400,000 per year. Add his pension and Social Security to this and he has done well, so you are right there is money to be earned when elected and serving in Office.
Had you chosen to be a politician/senator how many elections do you imagine you would have won?