Between becoming defence industry minister in 2016 and his departure from the full portfolio earlier this year, Christopher Pyne instituted the largest military modernisation project Australia has witnessed since World War II.

By May this year, when he departed parliament, Pyne had engraved plans for spending and equipment decades into the future. He had locked-in a massive spending program that will utterly transform the forces.

But that plan raises big questions, the most important of which is has the money been spent on the right thing?

The individual purchases that will shape the future Defence Force all form part of an integrated whole. The weapons shape the military, which is great - as long as the strategic challenges Australia faces in the future are ones that the military is optimised to deal with.

Two particular aspects of this plan are causing significant concern in the strategic community. The first is the amount allocated to big-ticket items. There is not a lot in reserve if the cost of any individual project blows-out in a minor way, let alone significantly.

The other issue is that the potential for significant technical development has been ignored, despite the projects' long time horizon. This seems inexplicable during a period where every year seems to bring news of dramatic breakthroughs in so many fields.

Let's take these issues in turn. Firstly, the huge issue around which the entire defence structure revolves: the nature of potential operations.

For the past 20 years the forces have been continuously, and almost exclusively, engaged in small-unit actions on land. Naval vessels have played a significant role in the international contingent in the Persian Gulf and air operations have likewise provided major support to deployed contingents.

Nevertheless, in not just East Timor but also Afghanistan and Iraq, it's the number of boots on the ground that have provided the relevant metric for success. Unfortunately, there's been a significant disjunct between the objectives assigned and the capacity of the forces to achieve them.

When he was Chief of Army, Lieutenant General David Morrison focused on preparing the battalions for conventional warfare. That's why the brief for the new armoured fighting vehicles insisted soldiers should be able to fire their weapons while closed-down inside the hull. While this might be useful in potentially chemical-soaked battlefields in Europe, it's of dubious utility elsewhere.

The reorganisation of the army has, similarly, emphasised fighting against a "peer" enemy, although the prospect of this actually occurring is almost negligible.

The assumption has always been that if the force is practised at this it will be proficient and capable of adapting to (supposedly) "easier" operations, such as counter-insurgency. The problem is, although the army has a fine tactical record in small-unit engagements, it's difficult to find any examples of real or lasting operational success in this regard since World War II. Asserting this isn't to blame the commanders for strategic failures in Vietnam, Iraq or Afghanistan: they're not culpable for big picture failure. The reality is that there is nothing simple or easy about irregular warfare.

Ironically enough the reorganisation has also seen specialist elements, such as the armoured regiment, split up into penny-packets and distributed among other formations. Similarly, the brigades currently lack any self-propelled guns, which means they couldn't realistically be deployed for the tasks they're supposedly meant to be capable of achieving.

Similarly it's difficult to see how the navy's plans to expand will ever be fully realised. The Australian Strategic Policy Institute estimates the new submarine will now cost some $73 billion (in today's dollars). This figure isn't a blow-out; it's just indicative of how expenses creep inexorably upwards while capability has a way of slipping down. But the design and manufacturing cost is just the beginning: the issues will really compound as the cost of operating the new equipment kicks in.

The navy has had, for example, difficulties finding enough sailors to keep six submarines operating and there are hard limits to further automation of the vessels. Nevertheless the current plan is to put a dozen new submarines in the water, plus nine frigates, three destroyers and two LHD's. This is an ambitious target when the navy can't even fully crew the current fleet.

The obvious fix is simply to pay sailors more, but that won't be an option without boosting, considerably, the budget allocation. It's difficult, however, to see where the money will come from. That's not least because the airforce will also be lining up with its hand out.

The F35 Joint Strike Fighter is, and will probably remain, the most capable combat aircraft on the planet. It's manoeuvrability and effectiveness is, nonetheless, limited by the capacity of the human inside.

The University of Cincinnati recently announced it had conducted a series of simulated test engagements between a human pilot and a plane controlled by artificial intelligence. The AI won - every time.

This doesn't mean the RAAF's new equipment will be outdated by the time it arrives. Nevertheless, if it's to remain effective it will require new, remote-controlled 'wing-men' to protect it and provide the heft to operate in contested airspace. That requires finance.

It can now be seen that Pyne's accomplishment was really nothing more than the compilation of an extensive shopping list.

In order to achieve the missions, more more money will have to come from somewhere, or the military will have to find a way of changing. Dramatically.