I'm not suggesting Russia go on the offensive, at least not for a long while. Both NATO and the Ukraine are hellbent on the "Not an inch of land" rhetoric. This works out great for the Russians - all they have to do is keep passing the ammunition and lobbing artillery shells, bombs, grenades at the advancing Ukrainians. With the current approach, sooner or later something's going to break - either Ukrainian determination, or their demographics. Remember, Ukraine didn't have the healthiest numbers even before the war. Then they lost a chunk of the population to emigration, they continue losing people at the front... How long until they get pushed into the situation of Paraguay ca. 1870, when they had to legalize polygamy to stave off extinction?
The western countries supplying weapons and keeping the Ukrainian economy afloat can't do anything with respect to people's expectations for a better life and shrinking population. Eventually a window for Russia to push will present itself. It might be in a year, or three, or ten. Until then, all they have to do is keep the meatgrinder going.
As for western arms production, keep in mind that western equipment is expensive. One of the first things to go after the end of the Cold War were military procurement budgets, because it was an easy way to save a lot of money. And western countries kept doing this for a long time, even after 2014. It's not the 1940s anymore, putting a couple of machines in an empty warehouse and spitting out ammunition the next day just isn't going to happen. Those are long-term investments, they require security, materials, qualified workfroce... There's a reason why the ability to manufacture tank and artillery guns in the UK has become Lostech.
