Ultimately, for the purpose of getting a Compostela, only the last 100 km have any bearing (200 by bicycle or horse). If you can show you walked the last 100 km continuously, with 2 stamps per day, you have earned the Compostela. It doesn't matter if you have got one stamp per day previously, or no stamps for significant sections (say, for example, taking a bus across the meseta). None of this will affect your qualifying for the Compostela. It may affect what they consider your start point, but that isn't recorded anywhere on the Compostela.
It could conceivably affect what they put on your distance certificate, if you ask for one, but even there I have never heard of anyone missing out because they didn't have 2 sellos per day in earlier parts of their Camino.