It doesn't mean that at all. If I live, as I do, about 400 m from my nearest bus stop how does making the bus stops further apart mean that I only have to walk 200 m to reach one. In fact I would have to walk maybe 600 m if that bus stop was removed to fall in line with your edict. You might be correct to say that I would on average have to walk 200 m more..
It also wouldn't cut bus journey times in half. It may reduce journey times a bit but not cut them in half. It would reduce the amount of time the bus was stopped by half (although even that is not true as more people would likely get on per stop) but as a bus journey is the sum of stopping and travelling time it really isn't likely that you could half bus journey times. You would have to assume that the bus travels much quicker between stops as well but it would have to really shift to get anywhere near.
Assume a 20 min journey with a generous 10 mins stop time as part of it. Let's half the stop time so that makes 10 mins driving and 5 mins stop time - still 15 mins and that's assuming that halving the number of stops would half the stop time which it wouldn't as the same amount of people still need to get on so in reality stop time would be more like 6 or 7 mins.. So 16 or 17 mins - maybe. Of course this is simplistic but still indicative.
So would this reduce congestion? Still the same amount of buses on the road just stopping less frequently but for longer? You would have to assume that buses are the cause of congestion rather than the much more numerous cars, vans, lorries, taxis and other vehicles. Of course in some places bus stops do stop traffic and cause congestion but mostly they are stuck in traffic (or maybe in bus lanes) with the rest of us. I don't think it would make a huge difference really.
Reducing car use, encouraging people to walk and cycle and providing an efficient cheap pubic transport network would be much better options and I don't think making people walk further to get on a bus really adds that much.