Why current professional philosophers aren't referred to as sages, in the contemporary era? Because referring to oneself as "a sage" would be viewed as, at best, exceedingly quirky, and, at worst (and this is the most likely outcome) deeply, deeply pretentious.
I don't think this is a bad question, but I'd push back on your assumption that none of the people who study philosophy are also practicing philosophy in the ancient sense. You mention Thomists, to take a single example consider Garrigou-Lagrange's "The Three Stages of the Spiritual Life" - this book is all about prayer and virtue and mysticism, but he was also a serious Thomist who did lots of academic work. And when I read Simplicius' commentary on Epictetus, it was quite close to what Christian writers in ascetic theology talk about including Garrigou-Lagrange (same division of purgatio/illuminatio/unio etc). In general Catholicism does not view philosophy/theology and ascesis as being really separable; John of the Cross, Augustine, Maximus the Confessor, you could list names for a long time, all of them studied academic philosophy seriously. Even Albert the Great, who you might think of as more of an academic than the others inasmuch as his reputation is as a natural scientist and commentator on all of Aristotle, wrote about mysticism and prayer. Other religions are like this too, I just don't know enough about them to say much, but for example Buddhism has a complex tradition of intellectual philosophy and debate, but it's pursued in the context of spiritual practice. Further, even philosophers who aren't at all "churched" - consider the philosopher Peter Singer, who lives as simply as possible and gives most of his money to charity because of a utilitarian ethic that is totally atheist. Or I know a professor who describes himself as a religious Platonist, and he definitely lives an upright life and volunteers etc. And then, even people like me who basically do treat philosophy as an intellectual pursuit, and aren't particularly wise or sage-like - few philosophers are sociopathic, anyway. It's hard to imagine someone who studies philosophy engaging in outright antisocial behavior and so on, because intellectual pursuits are elevating in themselves, and I'd say the same thing for mathematicians etc. (And there are socioeconomic factors, it need hardly be said). Grappling with the complex thinking of a stranger, especially a stranger you're biased against in some way, would probably tend to strengthen empathy in its own right (and this is not unique to philosophy of course). Certainly, though, philosophers were not generally referred to as sages or any similar term in the west, unless they had already been dead for a good amount of time. But in general people don't talk about their do-gooding or meditation or prayer, first because it would make you look like a jackass, second because all of these traditions see pride as an obstacle. Aristotle writes about pride as a virtue, but there's a difference between pride and arrogance. In the Phaedo Socrates says that every pleasure and every pain is like a nail riveting the soul to the body - but complacent contemplation of your own supposed virtue is just such a pleasure, and even though Socrates clearly did think that he had some special gift, he was usually respectful to others.