In the first production wave, the silicon yield is not so good, hence to salvage some "defective" chip, they create 3080, but as times goes by and the production yield improve, many chip is "perfect", so its better to sell them as the 3090 TI.
Considering that the 3080 and 3090 TI using same chip, if the yield is good, it doesn't make sense to sell good chip (capable to be 3080 TI or better) into "crippled" chip (the 3080), so naturally the 3080 production will be decreased, and the 3080 TI and 3090 TI will be increased.
They could disabled some part of "near perfect" chip to make 3080, but this is not without risks. Some years ago they try to do this kind of process (disabling some part of GPU), because the yield is so good but demand is high on lower level product, and it does not take a long time for someone to "modded" that card, enabling the disable part, effectively make that card function like higher level product.