The thing about Afrikaans is that it is closer to standard Dutch than various Dutch dialects. I can understand standard Afrikaans pretty well. But I don't think I could understand someone speaking Twents, Zeelandic or West Flemish. Even in a small country like the Netherlands the local dialects differ quite a lot from each other and often are not realy mutualy intelligeble, but Afrikaans is with Dutch (well maybe not mutualy, since even though people who speak Dutch can understand someone speaking standard Afrikaans, people who speak Afrikaans have trouble understanding someone speaking Dutch).
Personaly if the Cape colony remains Dutch, I think Afrikaans would have the same status as the local Dutch dialects. Basicly in the 19th and early/middle of the 20th century the lower (and part of the middle) class people speak just the local dialect/Afrikaans, while the upper (and part of the middle) class speak standard Dutch. When more people get educated the lower classes start to understand and be able to speak standard Dutch and use it when neccessary (like for example at work, at school, when doing official bussiness), while amongst each other the speak the local dialect/Afrikaans. Then when in the middle of the 20th century populair culture becomes more prominent (like television) and don't forget personal mobility (basicly people being able to move to other places in the country and even abroad) the local dialects become lessand less prominent to the point that in the ealry 21st century many dialects (and thus probably Afrikaans) are dying out. In the end Afrikaans ends up basicly Dutch, but with a small amount of different words and phrases. Kind of like the difference between standard Flemish and standard Dutch Dutch.