1) Liberalism isn't doing whatever someone wants (I think that's been well-repeated throughout) 2) Liberals are conservative on some issues while Conservatives are liberal on some issues (i.e. gun control. Conservatives tend to be more pro-gun while liberals tend to support stronger gun control.) 3) I don't know how it is in Mexico, but in America, liberalism is not the problem. Conservatives (who tend to be Republican, unfortunately) are the ones we need to worry about. Why? Because extreme liberals are not the ones yelling out all sorts of ridiculous notions about rape and pregnancy and trying to enforce equally ridiculous laws. For example: In New Mexico, a Republican lawmaker proposed a bill that would make it illegal for rape victims to get abortions for "tampering with evidence" which carries a felony sentence of up to 3 years in jail. It was extreme conservatives who made statements that follow MEDIEVAL mindsets that "real rapes don't result in pregnancies".
The question isn't how far will we let liberalism go. Its how far will we let the loud-mouthed extremist conservatives go because their opinions, their ideas on how our laws should be, are downright terrifying.
I'm not sure why we're talking about measuring the liberal-ness of ideas? Liberal-ness (as you seem to be defining it) is just "how different is this from tradition?"* It's... pretty expected that deviation from tradition (liberal-ness) keeps increasing? The only reason it wouldn't, is if societies tended to change back to the way they traditionally were a lot, and they don't.
That's why some people were confused by what you meant, by the way - in a lot of circles, "liberalism" is what people in the 1700s and 1800s called embracing capitalism, which is now considered a conservative idea. To them, liberalism was liberal in comparison to feudalism.
Based on the pattern of history, I'm pretty sure that people who are liberal for their time, support things that end up actually catching on at some point in the future, and don't cause anything especially bad to happen are the ones who are likely to have their ideas remembered as good. Because those will be the ideas that are *normal* to the people reading the history books. This doesn't mean they're necessarily actually better, just that their ancestors will judge them as better. As I evaluate things, the policies that are actually better are the ones that have the best consequences, which doesn't have much to do with whether they are "liberal" or not.