It so happens that the CBC published a story this afternoon which addresses this question directly.
There are several CBC Radio interviews in this story. You can listen to them via the web page. I have provided a summary of one of them below(Ukraine's potential counter-punch). The others are probably not worth listening to however.
CBC Radio's The House: Can Ukraine hold on?
The CBC interviewed Phillip Karber, the head of an American think tank and an expert on Russian strategy and warfare tactics. He has provided advice to both the Ukrainian government and to NATO.
He had the following to say (I have summarized it into several bullet points).
- Russia gave up on taking Kiev. They had some sort of plan, but we don't know what it was. The fight around Kiev was primarily an infantry battle and Ukraine's infantry was better than Russia's.
- Russia then focused on the east.
- Russian advances there were slow (1km per day) with heavy losses.
- Now nearing Slovionsk and Kramatorsk (200 km south of Karkiv). Battle in this area is dominated by artillery.
- West of Slovionsk and Kramatorsk is flat open steppe like Canada's prairies. Battle here will be dominated by armour. Whoever has the most armour and best armour commanders will win. This will be a game changer. Don't know who will win.
- Russians are "pretty beat up", but are reconstituting their forces.
- Every Ukrainian unit is already committed and there are no reserves.
- Arrival of Polish tanks near Kherson made a big difference.
- Ukraine have lost 50% of tanks, 70% of IFVs/APCs, 35% of artillery. They are down to being walking infantry.
- Karber was asked if the West have a strategy to supply equipment to keep Ukraine in the war. He said yes, However, they do not have a plan which will help Ukraine win the war.
- Lots of equipment has been given to Ukraine, but in the form of odds and ends. Training and maintenance is a "nightmare". Aside from the Polish tanks, they have not received a large shipment of weapons which can replace their losses.
- Only the US can provide large numbers of weapons of a single type as rest of NATO have already given what they can spare.
- Ukraine are preparing a counter-offensive in the south, with one objective being to recapture Kherson and relieve pressure on Odessa.
- They have a 60 per cent chance of success in reaching the Dnieper or in putting enough pressure on the Russians that they have to withdraw across the river.
- Unless they get a large shipment of high quality Western equipment however (tanks, artillery etc., not just small missiles) they will not be able to recapture the east side of the river.
- Russia will not initiate the use of nuclear weapons if the war goes against them, as it will not necessarily stop the war and it leaves no further room for escalation.
- War could end in one of two ways. The first is Ukraine defeat the Russian army and the latter withdraw as they did from the area around Kiev.
- The second scenario is Russia end up controlling the eastern part of Ukraine. However, this will not be the end of Russia's ambitions and they would look to re-establish some sort of "Russian Empire".
Putting several of those points together, it is an interesting question as to how Ukraine's exceptionally heavy losses in terms of armour will affect their ability to fight on the open steppe.