Protocols scale in layers. The base layer is design to perform specific operations.
Discussion
Your explanation appears incorrect in light of the existence of Monero, Litecoin, and doggie coin
What’s your thoughts on how many layers will be needed for BTC to successfully work?
The implementation of layers for the applications that will inevitably form what you may refer to as the entire protocol stack will be determined by creative technological revolutions that we cannot even yet comprehend, based solely on the fact that we are currently only in 16 A₿….aka: we are still early.
In the same way that 16 years after the ARPANET [DARPA] initiation around the 1960s there was no full comprehension (as we know it now) of how SMTP would grow and be widely used from the 1980s onwards; as an emergence from its predecessors in the 1970s - we are going to have similar developments on this paradigm shift.
When tried and tested solutions are frictionless enough for grandparents to adopt them, then the visibility will begin to become even more apparent.