illustration (attribution, if any possible, is at the end of the article)
Frequent questions of beginners are about how many people were enlightened in the past, or how many are enlightened today… And if the questions are about the present, they can easily drift toward « How do we know they are enlightened? »
These questions are missing the point. They're traps of the ordinary mind, which seeks certainties and the safety of a guaranteed recipe for awakening: « I'll do the work only if I can be sure that… »
For a start, such questions are based on the delusion of separateness; once the questioner will practice seriously enough, insights into selflessness will weaken such questions to the point of irrelevance.
To continue, there isn't an external pre-defined manifestation of awakening. According to early Buddhism, you might have some rather systematic manifestations when a Supreme Buddha is born, awakens, or dies… but the awakening of paccekabuddhas or of arhats don't share these traits. One of the key traits of awakening is appropriateness to the situation at hand, to the context; it is therefore not surprising that there isn't a nicely preconceived, fixed manifestation of awakening, since any manifestation is context-dependent!
To drop self-centric perspectives and therefore start practising really, you might want to ask yourself:« why would others need to 'broadcast' that they're enlightened? »
It's likely you'll come with many answers revolving around you. You may phrase them in more generic terms but you're likely included in the beneficiaries. For example, you might think « so that witnesses get greater faith in the Dharma », but you probably mean « so that I get greater faith in the Dharma, and get reassured I'm on a risk-free (or at least low-risk) spiritual path… » A self-serving, reassuring belief isn't what the Dharma is about.
The belief that "you've met" or that "you're meeting" an enlightened person may well be a lot more dangerous (for your spiritual growth, and for others') than the belief that "you might meet" an enlightened person.
Awakened beings might therefore refrain from giving you certainties, for your own benefits: too much certainty about the Dharma leads to clinging, and to conceit, it hinders questioning, it hinders studying, it hinders dropping all views, it hinders leaving the raft after crossing to the other shore…
Moreover, paccekabuddhas have awakened (by definition) but they stay silent. They have good reasons: they freed themselves from the specific defilements they had, but they cannot guide others because they don't know much about how other defilements tie one down. They might not even had fully understood how they freed themselves! Not being able to guide others, they remain silent rather than mislead.
Similarly, even after their awakening, arhats tend to limit themselves to sharing the Dharma of a Supreme Buddha, because they only mastered their 'own' defilements while the Buddha knew (thanks to his long Bodhisattva career) the antidotes to all defilements: for the benefit of all, it makes sense to share the Dharma rather than the arhat's own individual, specific experience. [As it happens, what the ordinary mind imagines the Dharma to be is usually too narrow a view though… so an enlightened being might teach in unexpected ways and not just repeating the Dharma you already know! Don't presume you already know the antidote to your ignorance!]
Finally, it is very common that people easily see qualities in people far away and with very different circumstances from theirs (e.g. a lot of people see some qualities of the Dalai-lama) while they cannot accept that those close to them would be "more" enlightened, or wiser, than they are. People can experience the former phenomenon with 'manageable' envy or jealousy (e.g. they can accept they were not born in a Buddhist culture), but they cannot handle the same sentiments if the person is close: if circumstances are similar, competitiveness kicks in and the ego rebels at the idea of being a 'loser'… People then prefer not to see, rather than accept that others may be enlightened! Therefore, the key question is not about others being enlightened or not, but about you and your ability —or lack thereof— to see without biases…
As long as you're biased and your ego might get the best out of you, awakened beings might, in order to help you, refrain from 'announcing' their awakening: they thus refrain from triggering the 'competitiveness' that would blind you from the lessons they might share!
Stop looking for other enlightened beings, and work on yourself, study your mind, your biases, your ignorance… Drop the views that bias your perception, drop the prejudices, the tendencies… Once you'll cease ignorance, once you'll see reality as it is, you'll also see who else has ceased ignorance too.
photo © Denis Wallez: "Buddha" (9th-10th century) at the Art Gallery of the Māratha Palace in Thanjavur (India)… Semi-lotus posture?