Keep on dreaming AvTvM
quite to the opposite: camera makers are really dreaming if they believe, many potential buyers of mirrorless system cameras are wiling to pay MORE for a CHEAPER to produce mirrorless camera compared to an equally capable DSLR. Apparently they have to learn this the hard way. :-)
And a perfectly competitive marketplace, with lots of sellers selling essentially identical goods and/or services, would teach them that rapidly. Unfortunately, we don't have a perfectly competitive marketplace.
Like you, I expect mirrorless FF cameras to largely replace DSLRs. There is, however, the question of delays and when they occur. With a mirrorless camera, there will always be a delay from when the event occurs until it appears on the EVF, a delay that does not occur with a DSLR. However, the DSLR has the delay caused by having to move the mirror, which the mirrorless camera eliminates. So, pick your poison.