Are recent tech layoffs revenue related or top down instructions from VC?

Since Twitter's layoff by the new boss, it seems that more tech companies are following suit, citing various reasons, especially like economy downturn. How true is that? It feels that investors are the one dictating the layoff, seeing that Twitter operates 'just fine', that growth at all cost strategy can be culled, and that this is the best time and opportunity to announce layoff witbout much backlash.