>>515649984
>the war is a drain on Russian budget (money spent on military gear cannot be spent on civilian projects/development)
Excapt they can and are.
A lot of money was put into (((international reserves))) every year, it's exactly the same money the West (mostly the EU) seized in February 2022 and Ukraine has been offering to share.
It mostly stopped. Of course, exporters keep at least a part of their revenue abroad, sometimes even in Western banks, But it's much less than 4-5-10 years ago. 
A lot of money have been brought to the MIC, they pay salaries. Money stay in Russia, because people just spend it on their expenses (food, clothes, utilities and so on), The same has been happening with soldiers who send huge chunks of their high salaries to their families.
Plants have money to buy new equipment. Yes, a big part of it is import, mostly Chinese, but a part of it is still domestic. And so on, and so forth. Actually Russia used to bleed money in the peaceful time, but now in some paradox money stay here. And a lot of people, some powerful people are interested into this going on for a long time.
Men not working in factories/offices forced business to pay higher salaries instead keeping bigger profits and sending them to Western banks, spending them in Cot-d'Azur or Milan boutiques. Yes, pro-Western forces lobbies migrants as extra workforce, but many migrants don't want to go into the country fighting in the war.
Yes, sanctions matter, but there are other advantages, including literal spies, saboteurs.and agents of influece leaving the country. 
I look at Putin's behaviour, I hear Medinsky's speech about Russia being ready to fight for 20 years. I understand they aren't madmen, despite of all efforts of Western media to depict them like that. Actually they are rational, cynical and calm people. But if they are so self-confident, it means they know the bigger picture and are sure there are more advantages than disadvantages (which exist, of of course).