There are still plenty of phones around that have both a 3.5 mm jack and an SD card slot. Sony have them, as well as the Samsung Galaxy A line, the Xiaomi Redmi phones and quite a lot of others:
m.gsmarena.com
Granted, you may still have to use a dongle if you want to use hard to drive phones that require a lot of power. Personally I just tend to leave those at home.