In fact, when things are tight is the very moment you should go all in for R&D.

Let's clear up something simple people forget: when things are tight for you, they are normally also tight for your customers. In fact, that's generally how they become tight for you.

So you can forget investing in production and sales when things are tight. Things are tight because the world is in a period where your customers aren't buying. You won't change that by trying to sell harder.

However, small research projects are an incredibly cheap way to learn things and invent new technologies. When you're not encumbered by turning things into products, you can discover at a frightening speed. So you spend on research when the times are tough, and then when things go better you have a huge backlog of technologies you can apply right away.