Why Aren't There More Deists?

Imagine an argument that went as follows:

How could you not consider that there may be intelligent life elsewhere in the universe? There's no reason to think that it's impossible since life appeared on earth. With there being 10^23 stars in the universe, with planets being found everywhere we look, it wouldn't be absurd to think that the conditions that allowed for intelligence life on this planet may exist elsewhere. And that's only taking into consideration intelligent life as we know it. Although more speculative, we don't have reason to exclude other paths to intelligent life under very different conditions. The range of possibilities and the vastness of the universe are strong indicators that we are not alone as intelligent life in this universe.

And then followed up with:

So UFO sightings ought to be taken as being caused by extra-terrestrial intelligence, crop circles being marks of these extra terrestrial intelligences, and alien abductions being authentic experience of these aliens.

If you weren't already convinced of the reality of alien interference on this planet, would you find the argument convincing? I'd wager not, as the original argument does little to establish the reality of interfering aliens. In other words, there's a gap between the premise and the conclusion.

This might sound like a contrived example, but it's the kind of argument I see all too often from theists. Just substitute in the cosmological or design argument on the premise, and the conclusion being the interventionist deity they happen to already believe in.

It's not just that the arguments don't validate their particular theism, it's that they don't validate any form of theism! There's a huge gap between the arguments and the conclusion, with much left resting on assumptions that are snuck in with the individual's prior belief.

What strikes me as curious is that there aren't more deists around. If one were to follow the arguments, deism would be the most parsimonious conclusion, yet deism isn't the view defended with such arguments.

Now I am fully aware that the human mind isn't completely logical, and that arguments are more justifications of an existing position than something followed to their logical ends. Even so, it does surprise me that there isn't more of a spread among believers. The range seems to be from externalising to internalising the personal god, rather than from a personal to an impersonal one.