That happens in basically every industry. The problem is that if you double your own estimate, but no one else does, then your project doesn't get selected. Also, if you double your estimate and go ahead with the project, it will have a psychological impact which causes wasteful spending and slow work that will result in additional overruns...
So, it applies to all of the recent large solar, wind, and battery projects... which appear to hit their budgets and dates? Or are those not megaprojects?
Most megaprojects have mega complexity. In contrast, wind, solar and batteries are scaling by having many units, feeding in to a dumb grid, and don't have the complexity explosion.
Distributed generation and smart loads were invented to add enough complexity (technical, regulatory) to allow them to achieve massive system failure :-)
This is why I think solar can win in the long term (wind already has won) - just scale up linearly. Doing so is geared toward standard assembly line production, standardized installation for the technicians, regardless of scale.
