Comment by keyringlight

I think one of the challenges is that game designers have trained up so well at working within the non-RT constraints (and pushing back those constraints) that it's a tall order to make paying the performance cost (and new quirks of rendering) be paid back by RT improvements. There's also how a huge majority of companies wouldn't want to cut off potential customers in terms of whether their hardware can do RT at all or performance while doing so. The other big one is whether they're trying to recreate a similar environment with RT, or if they're taking advantage of what is only possible on the new technique, such as dynamic lighting and whether that's important to the game they want to make.