It depends on the tournament size.
There is no "should."
I guess if you "should" be profitable, you need to make the final table often enough that the sum total of your payouts are greater than the sum total of your buy-ins. But if you "should" be making a an average 20% ROI, or you "should" be making a certain amount of money a year those numbers are going to be different, as they rely on different factors.
It's also a numbers thing.
The bigger the tournament, the harder it will be to go far, but the bigger your payment will be when you hit. Obviously 10% of players in a 90-player tournament make the final table, 1% of the people in a 900 player tournament make the final table, and .10% of the people in a 9,000 player tournament make it to the final table (that's one in a thousand). Obviously you can't expect to make the final table in a 9k player tournament 10% of the time, and obviously you'll want to be doing better than 10% in a 45 player tournament.