I've not seen anything discussing Argentine military strategy in any depth. I'd be very interested if anyone has any sources.

However there are some basic comments that can be made.

Firstly, up to and even after the dispatch of the British task force, the Argentine junta did not really expect to have to fight. Even if they did, the navy and air force had a realistic prospect of defeating the British force.

From a diplomatic perspective, sending more troops could be seen as a provocative and aggressive move. Perhaps up until the sinking of the Belgrano (2 May) there were genuine diplomatic hopes. This happened after the British task force established its exclusion zone around the Falklands, eliminating any chance of reinforcement.

The Falkland Islands are a lot closer to Argentine but they're still 600km away. Supply (or perhaps distribution) was a real problem, and I think possibly the key problem. By the time British forces began to land, Argentine units were going hungry. The Argentines had to not just supply units but build up stockpiles for the length of the British blockade. In the event, it was three weeks between the arrival of Royal Navy ships and the first landings.

Which brings up another point. From 12 April, Britain declared an exclusion zone around the Falklands. It would still have been possible to fly in troops and equipment, but only at a modest pace (since the islands did not exactly have a large airport). Any reinforcements moved by sea would be at risk from British submarines - a very real risk as HMS Spartan was on station by this point, and the sinking of the Belgrano later illustrated the submarine threat.