You are taking about a century gap and technology is advancing at such high pace that it's impossible to make any perfect speculations.The internet was developed in 1990's and now we are nearly 20 years ahead and now we can't imagine life without it.Bitcoin developed in 2009 was mere a joke for many and claimed to be bubble but now in just 12 years it is becoming mainstream and adopted as legal tender by many countries so we can't say what will happen after 100 years.The mining will be carried out for another 19 years so it is supposed to be there for that time period and network will remain the same with some miners addition or deduction.But if you say about 100 years I can't say anything.