The discourses present the teachings of the Buddha as potentially addressed to everybody, although they also make it clear that not everybody will end up following them.
On one occasion (AN 10.95), the Buddha is asked whether his teaching leads to the salvation of the whole world, or only half of it, or even less. The Buddha remains silent, because he does not know how many people can take up the practice and reach ultimate freedom. He only knows how to do that, which is what he teaches.
When the Buddha approaches a potentially interested audience, his teaching is deployed in two steps. He first draws attention to the domain of moral action and intentionality, trying to get the audience seeing the dangers in greed, aversion, and ignorance, while instilling thoughts of generosity, friendliness, and letting go. If the audience is well-disposed towards the latter and understands the importance of abandoning appropriation, then the Buddha introduces his own distinctive teaching about the four noble truths (SN 56.11).
This two-steps strategy suggests the idea of making a first selection between those with a potential to progress further, and those for whom the teaching won't make any sense. Like a skillful gardener, the Buddha seems interested in understanding where to find the appropriate ground for planting the seed of his teaching.
This teaching remains a sealed shell without a basic understanding of the inherent problems with greed, aversion, and ignorance, and some aspiration for a profound redirection of experience towards the attitudes of non-appropriation and letting go.
But even when this first step is taken, it does not entail necessarily that everybody will follow through. Some will be satisfied with just hearing the Buddha's words. Some will make an attempt. Perhaps only a few will bring together the necessary mix of personal qualities, perseverance, and determination necessary for moving forward more significantly.
In practical terms, this means being able to undertake for a sustained period of time practices of restraint (precepts), composure, and investigation into reality (especially into the impossibility of any form of appropriation). When all these elements works together in the right way, a breakthrough can be expected (sotapatti, the 'entering into the stream'). This is a moment in which one gains such a first-hand and profound understanding of what the problem actually is, and they will have no further doubts or worries about what needs to be done (although fully doing it will take some more time).
But this is a relatively rare achievement. What about the others? Being exposed to the Buddha's teachings has at least one major effect: it makes it apparent that any attitude based on greed, aversion, or ignorance is not a necessary predicament but a choice, something one is taking up deliberately. Even when it feels like that one could not pull oneself out of this tangle, it remains the case that there is no inherent necessity in following along with what these three bases of action prescribe. In short, the Buddha's teachings make it apparent that we have to make choices all the time, even when we'd like not to take responsibility for them. And wherever there is a choice to make, there is also a degree of freedom. Even for those who do not (decide to) progress towards ultimate freedom, the Buddha still makes it explicit that this is precisely how they exercise their freedom.
Freedom is the ultimate goal of the Buddha's teachings. The fact that not everybody must achieve it, but that it remains a possibility for everybody is thus consistent with the underlying ideal that inspires the discourses.
Does the Buddha care for those who do not take up the teaching and do not work to gain greater freedom? Yes and no. In one discourse (MN 137) the Buddha presents two scenarios: (1) some disciples do not want to listen and do not make progress, while others do; or (2) they all listen and make progress. In both cases, the attitude of the Buddha is the same: he is neither pleased nor displeased, but remains 'serene' or 'equanimous.' This is not because he does not care. He does, since the whole idea of spending his life for teaching to others is based on compassion and a desire for seeking the welfare of others. But he knows that it is beyond his power to make them doing anything with that teaching. His equanimity is an act of respect towards the freedom of others to determine for themselves what they want to do.
The gardener can prepare the soil and provide the seed with the best possible conditions, but the rest is up to the seed.