Most Bnei Torah today, as in the past, work in jobs considered appropriate for a Ben Torah, such as communal civil service (teachers, soferim, etc.), scholarship, etc. Then as now, many Bnei Torah also run businesses.
The biggest change is that the percentage of Bnei Torah is higher, since the people who 300 years ago would have been a frum Am ha-Aretz, is not secular, and probably vanished due to assimilation – and those who remained frum remained frum becuase they decided to be Bnei Torah. History suggests there is really no option between assimilation (meaning giving up being Jewish and joining the general population) and being a Ben Torah. One can’t raise kids to be a little bit Jewish.