It's the tradeoff between local computing power and bandwidth/latency. It flips back and forth every couple decades based on what's expensive and what the last big advance was.

Even within the current era, render on server, render on client, ajax (the mix), etc.

We're seeing it now in gaming. Vidcards are the cost of a whole system now, games have become huge, and fast storage is still expensive; but bandwidth is increasing along with A/V streaming being perfected, so someone figured out how to minimize apparent control latency and now games are streaming. Once vidcards get cheap and SSD storage capacities catch up to 150GB games it'll flip back until the balance tips again.