Historically I think it would be incorrect to identify the default political stance of Quebec to be left-progressive. Prior to the 1960's Quebec was essentially a rural-Catholic society which tended towards large families and the government was basically all church and business for most of the [early 20th Century] (http://www.canadahistory.com/sections/eras/cold%20war/Quiet%20Revolution.html).

Catholic leaders in Canada have tended to distance themselves from socialism and no NDP (social democratic) government has ever formed in Quebec, although some prominent PQ politicians had a socialist bend in the last thirty years or so. Jacques Parizeau, and Gilles Duceppe had a social democratic bend even though Parizeau famously believed that Quebec separatism failed because of "money and the ethnic vote".

The key fault line in Quebec politics in the 20th century was nationalism and not right/left alignment. Even most right-aligned Quebec politicians did things like fund the arts because it was good for hearts and minds (morale and propaganda). Most of these right-aligned politicians also put in good social services (such as baby bonuses) but that was often viewed as a matter of supporting families to have lots of French-speaking Quebecois babies. Quebec governments have also been fairly interventionist in the economy through policies like supply management to preserve the dairy industry; again this is related to keeping local industries propped up for nationalist reasons. Think of nationalism as motivation here, not soft-touch socialism. Remember this is the region of Canada that gave North America [sign police] (http://news.nationalpost.com/tag/quebec-language-police).

Consider that the majority of famous Quebec politicians are Conservative or centrist. Lucien Bouchard and Jean Charest were Conservative federal politicians. Jean Chretien ran a very fiscally conservative Liberal government (unpopular in Quebec) and [Pierre Trudeau] (http://historyofrights.ca/history/october-crisis/) was left socially but had enough of an authoritarian bend that it's hard to think of him as a leftie.

Brian Mulroney was something of a neo-conservative pioneer and counted Rene Levesque among his supporters. Rural Quebec was part of Stephen Harper's early governing coalition. The assumption that Quebec's default political stance is left-leaning is incorrect.

I can't speak to the other regions, but in the case of Belgium, it's not really the linguistic divide that determines the economic politics of either of the regions. The main determining factor seems to rather be historical presence of industry - and in turn, this can largely be traced back to availability of resources such as coal and iron. You can see it on this map, with the former industrial belt of Belgium being situated from Mons to Verviers. Industrial areas have always been fertile ground for socialist politics, while non-industrial areas tend to gravitate towards more conservative or liberal politics. Here's a map of our last federal elections. You can see the old industrial belt.

At the same time, that map shows that it's not as easy as Francophone = left wing, Dutchophone = right wing. Wallonia has sizeable portions where the liberal and christian democrat parties hold sway. Similarly, although you can't see it on this map, Flemish cities like Ghent, Antwerp and Leuven have a very strong socialist tradition as well - Flemish industry was mainly concentrated in its cities, focusing more on textile rather than coal/iron industry. There's also Limburg, a Flemish region with its own coal seams and industrial history, which also has a strong leftist tradition.

So in short, language isn't the determining factor in regional economic policy here in Belgium.