In it's simplest form, liberalism is like the most famous equation known to the modern world; 'e=mc2', or Energy = mass times the speed of light squared.
Almost all modern empirical knowledge, especially in the sciences of origins and fates, is based around that equation. It's not just an equation for atomic bombs. It's an equation for the beginning of our universe and the future of our communication systems.
The liberal equation is similar, but easier to understand: (initial belief + recent objective data = new and improved belief).
That's it. That's all. End of story.
Believe it or not, conservatives have this same mindset, but it is usually adopted multi-generationally instead of inter-generationally.
Today, very few conservatives would agree that slavery was a character trait of morality. But less than 200 years ago, they did; and they defended it adamantly with the book of Leviticus in the Christian Bible.
At the time, abolishing slavery was a very liberal idea, and it was bad for a lot of businesses. However, at some point, a person has to put their morality in a bit of a hierarchy, and if the general well being of a human is not at the top, then there is a defect in that person's belief system.
Is capitalism a good thing? Absolutely. I would argue that there is no freedom without it; but, people come first. Capitalism is good at supply and demand and setting prices, but it is woefully inadequate at determining right and wrong, or if you prefer, good and evil.
That said, over the last 40 years, liberalism has been painted with a broad brush by neo-conservative groups that are not so "neo" anymore. They are now the ruling branch of the de facto 21st Century GOP. And, under that broad brush stroke, you really do find a lot of fault with what people now consider to be "liberal" ideas.
Therefore, liberals essentially need to keep their sights set on the malleability of their own mindset as well and redefine themselves for what liberalism really is - the mindset that initial beliefs plus recent objective data equals new and improved beliefs.