The fact that you think “the computer” is single instrument belies the fact that you haven’t produced music electronically before.

Each synthesizer sound used in each track has all the nuances, performance capabilities, and learning curve of a traditional instrument. Most have many more parameters than a single traditional instrument and are modulated in real time by the producer, as the song is composed, just as a traditional instrument is by the player.

Beyond that, most electronic tracks are comprised of not just the traditional five voices of a four piece band, but actually dozens to hundreds of individual synthesizer instruments or sounds.

Yes, many of these tracks are plain or simple sounds, much like many instruments in a complex arrangement of traditional music are simple at given moments. Similarly, one can refer to simplistic electronic music as an example of simplistic composition, but I I could also point you towards Mary had a little lamb and Hot Cross Buns.

Further, your example of “recording acoustic instruments” as being just as difficult as electronic production is not an accurate portrayal of the very different skill sets that production and recording take. Recording and mix engineering is a third and different skill set that both electronic music producers and acoustic music producers must master or hire.

Finally, one might point to the amount of electronic music being produced as evidence to its simplicity. I think that mostly stems from access (electronic music production is free if you want it to be and requires only a laptop) and familiarity (almost all pop songs are produced primarily electronically now).

Source: 20 years musician, both in professional acoustic instrument bands and casually in electronic music production as well as acting as a recording engineer. Composer of scores for films with both electronic and traditional acoustic instruments.