it isn't the length of time to travel between gates that is the problem. that is instant travel. what the problem is is the 50,000+ years it takes to get between systems to set up the next Stargate. I base this on the fact that at our tech LL right now it will take us 50,000 to get to the alpha Centauri system.
the other problem is the hyper drive engine costs 1 million dollars, give or take, to build.
i cant see a Stargate costing less than 1 trillion dollars per gate. you need two of these to work so each pair would cost 2 trillion dollars and then you don't get to use them for 50,000 years.