You can have sufficient bass with a decent 2.0 system as well. The goal of a good 2.0 sterio system should be to provide a good balanced sound (that includes lower frequencies - bass as well) covering most of the frequency range audible to us.
I have heard 2.0 systems that would make you feel there is a subwoofer hidden somewhere there. But to truely enjoy music to the fullest sometimes we dont need that extra bass. The extra bass can overpower the other frequencies and hence you may miss out on other frequencies (vocals, upper frequencies). Also 'unbalanced'/'colored' sound could actually contribute to listening fatigue.
I think to be happy in longer run the goal should be to have a very transparent/netural system in begin with. Once you have that in place then you can tweak the system to your sound of liking. There are many ways to fine tune the system. Example you could add a component that 'colors' the sound example and interconnect that could make the sound 'brighter' or 'warmer' (Disclaimer: these words mean different things to different people but this is the best terminology we have available). There are interconnects that can significantly boost the Bass.
Liking more Bass is a preference that can be achieved. It would be nice to start with a transparent system and then tweak it to your liking. But once you start with colored sound then going reverse could be not that straight forward
This does not mean a sub is always undesirable. There are cases when you need it. But it also does not imply that a 2.0 system can not do justice to the lower frequencies.