You make it sound like RTK is immune to GPS signal loss,if I am wrong please correct me,but I think any system has to be able to see the satellites to function.

Point being all systems can fail,if there is any problem seeing the satellite,or simply satellite failure.

I might also add that sub inch accuracy is just a dream for many RTK users because most of the inaccuracy is because of factors that have nothing to do with repeatability or satellite drift.

I could expand but anyone who has done much work with GPS with any degree of accuracy knows what I am referring to.