That is a good point and while Canon is on record as saying no new EF lenses will be developed, I have not heard of shutting down production of any either.

But, there is a second level to that as RF lenses are at a premium price point and right now EF lenses are coming in at a discount. For example, at B&H right now the RF 70-200 F2.8 is $2,700, the EF 70-200 f/2.8 III is $2,100, and then there is a new EF 70-200 f/2.8 non-IS for $1,250. I actually do not see the EF 70-200 f/2.8 II. At 24-70 f/2.8, the RF is $2,300 while the EF v II is $1,900. So, as people switch to the R system, they could buy an adapter and pick up EF lenses. Canon will continue to populate various price points with their products, which is very much a Canon (and good business) thing to do.

I am intrigued that the EF lenses are as high as they are (I haven't looked for ages). Either they are still selling well so Canon does not see much of a need to drop their prices, or Canon created an inventory and feels no need to move that inventory at this point.