It is highly radial, it radiates from Budapest. A single crash on the M0 in Budapest can gridlock the whole of eastern Europe for a day.
Except it doesn't, due to the alternative routes. The southern section of M0 underwent some refurbishment recently, and while it cause some jams, Romania and Bulgaria did not starve to death. You know, road networks are not built up in a way, that you either have motorways or swamps with radioactive waste, and nothing in between (except in Lithuania maybe).
But more importantly, and you are not the first one to bring this up in a thread, so I will elaborate:
the Hungarian motorway network is being built mostly for the needs of Hungarians, as we are the ones who mostly use it.
Yeah, half the Balkans goes through the country, when they are going home for Christmas from their blue-collar jobs in Munich. But other than those few special occasions, the overwhelming majority of cars on the network belong to Hungarians. And
in the overwhelming majority of cases, we either go to or from Budapest or go to and from Lake Balaton (especially in Summer). I know, if you are just a kid drawing lines on the maps, it would look so nice to have a line between Pécs and Szeged for example. But there is barely any need for that, so it falls way, way back on our priority list. I am not saying that nobody would benefit from such routes, but their numbers are way too small. So it is among the plans, but there is no urgency.