It really depends on exactly what you mean by some of these terms. Some forms of social liberalism are free (or nearly so). It costs us nearly nothing to establish marriage equality, legalize marijuana, adjust policies to remove systemic prejudices, etc. Other forms, such as healthcare, wellfare, foodstamps, social security, college educations, have price tags, sometimes very high ones.
Similarly, fiscal conservatism, as I see it, is more of an approach to how one spends rather than how much. I look at it just how like I’d budget my own finances. Some things are really expensive some things are really important. Very few people are going to argue that cheap important things should be bought or that expensive unimportant things shouldn’t (though some might argue which ones are or aren’t important), but how do we prioritize in the less obvious situations? I see someone who is fiscally conservative as being the guy who is a penny pincher, they’re only willing to go into debt for something critical (like a house or car) and even then, they might get a beater car rather than something they want more. Very few people that isn’t living on their rich parent’s dime looks at credit cards as free money.
Very few people are going to describe themselves as not fiscally conservative. Everyone realizes that money has to come from somewhere. The real problem is that not everyone can actually agree on what government programs are necessary or important and worth potentially going into debt for (or, as it really is, going farther into debt for) and which ones can be cut. Pretty much everyone who says they are socially liberal and fiscally conservative will have a different idea of how to approach these problems, and as such, it’s pretty much a meaningless descriptor.
The problem is, unlike our everyday lives, we treat government debt with a lot less concern. I may spend frivilously, but eventually that WILL come back to me, often pretty darn quick when I can’t make my rent or my credit card bill or can’t get that sweet new car or whatever I really want. When our government does it, it can take decades or generations before we really start to see the effects of that debt piling up, and that cost is spread across everyone, so it’s ultimately less painful too. So, even people who are more risk averse and conservative in their spending in their daily lives are probably at least a little less risk averse when it comes to government spending.
So, this is, in my opinion, exactly why, as much as I would love to see a third party rise (and I, in fact, have been strongly supporting one), I just don’t see it happening as long as we continue to look at issues this way. We’re always going to see those willing to spend more as fiscally irresponsible, even if it’s motivated by a great deal of compassion for wanting to help people, and those who don’t want the government doing certain things as uncompassionate, even if it’s motivated by a fiscal concern for things that are even more important. So, instead, we end up with two parties each painting the other as that other extreme version. Frankly, I don’t think it’s compatible because it’s asking the wrong questions.
A big goal of those who call themselves “economic conservatives” is often deregulation. Deficit reduction? Not so much.