>>Yes, that's why the E8 theory looks promising.
Hum,
yeah, most string theorists already thought that the E8 x E8` gauge group / Heterotic string would be able to describe all the particles and forces that we see (this is the simplest model to include all the forces including gravity and known particles).
The real discovery is the `pattern` that emerged that seems to describe groups or families of certain particles and related forces. The difficult part was that `pattern` is best viewed in 8 dimensional space so it wasn't easy to first see that structure. But now that it is found we an make predictions how certain particles are related to other known/unknown particles.