The rate limiting is basically factory capacity, yes. Simplified process:

- Czochralski purification of silicon to produce a "boule"

- saw boule into "wafers" (surprisingly important, see "reduced kerf diamond wire saw")

- wafers can be used for microchips, or doped into solar cells

- apply contacts to top face

- package into a panel with glass and aluminium frames

The "wafer" market is somewhat independent. Purification depends on the price of energy (it's very energy intensive). Better sawing reduces waste and increases wafers per boule.

More factories come online all the time. Panels themselves are now extremely cheap, and it's worth looking at "balance of system" (labour, permitting, frames and racks, inverters).

I believe market data firms track all the relevant info, although they don't necessarily give the resulting info away on the internet.