The purpose of studio monitors is to mix recorded music. While one wants extremely accurate professional studio monitors which reproduce a broad frequency range, one also has to mix music in such a way that it will sound good on the kinds of inexpensive consumer-grade speakers and headphones that consumers have in their homes and cars.
This is why one does not want to mix recordings on a speaker system that would have tons of heavy bass, added on, using massive subwoofers. If you mix in that environment, then when the recordings get listened to by the people that buy your music and play it back on their ordinary home stereo systems, in their cars, or in their iPhone earbuds, they will hear something drastically different than what you intend for them to hear and what you heard in the studio when you did the mix. This is counter-productive.
Back when I was in professional recording studios, in the 1980s and 1990s (home studios of any sort were very rare in those days), they always had a set of expensive stereo monitor speakers with large woofers and prodigious wide frequency response, but they also had one or two other sets of inexpensive monitor speakers with much smaller bass drivers that were there to represent what people used in their homes and cars. The ideal was to create a mix of the recording that would sound good, on average, whether it was played back on any of these different types and grades of monitors.
Although this is outside of my limited experience, I understand that there are now certain mixing and mastering plugins and signal processing devices available that are designed to encode signals into your mix that are capable of creating extra low bass frequencies (perceivable to the listener) that are reproduced when the recording is played back on consumer-grade speakers or headphones. These kinds of products employ "psychoacoustic bass enhancement technology". One example is the MaxxBass plugin by Waves. Its product information says that it "extends perceived bass response by up to 1.5 octaves".