Clearly, Blu-ray (including 4K UHD) is in its death throes, as far as sales of BDs and consequently new models of Blu-ray players go. Streaming has won, and is the present and future of video. As a form of distribution to the consumer, streaming is cheaper and the content is better protected against piracy, and so a winner for the content owners. For the consumer, streaming is more convenient and a one-time rental or monthly subscription is cheaper than buying players and tons of DVDs or Blu-rays for most content that gets watched only once. One can also "buy" online-served videos (which is more a fixed-price permanent rental, really) for content one intends to watch repeatedly.
Most major player manufacturers have announced that they will not be designing any new standalone Blu-ray players. They will continue to make and sell existing models as long as it is profitable enough. I think players for integration into (desktop) computers will be made for longer than that, though eventually optical drives will be phased out even there. For those of us left holding a bunch of treasured DVDs and HD/UHD Blu-rays that we spent enormous sums acquiring, we can only hope for perhaps one last round of player updates from a couple of manufacturers to get the best out of our optical discs. And of course stockpile a few players for when they are no longer manufactured. I was in no rush to update to 4K UHD, and was caught entirely off-guard by Oppo's exit from Blu-ray players. I finally bought the Sony UBP-X800M2 this January for US$220 from a brick-and-mortar. It has been fine so far. The "Mark 2" is important, as it refers to the inclusion of Dolby Vision decoding primarily. Some resellers on Amazon are still selling the X800 which is the "Mark 1", so beware.
Dynamic HDR capability to decode Dolby Vision and HDR10+ (not just HDR10 which scales the luminance of each frame based on a (static) single average luminance for an entire movie, and not based on average luminance (dynamic) calculated per frame) are I think important features to look for in a player, if you have or plan to buy a bunch of 4K UHD Blu-rays with dynamic HDR content. I only have a 1080p TV as yet, but I have read and heard that HDR makes more of an impact than 4K vs 1080p, in TVs that support it. It is unclear which of the two competing specs will win out or whether they will co-exist for a long while. DV has the momentum in number of titles and uses 12-bit color, but HDR10+ while using 10-bit color is license-fee-free for all concerned. So I would hope for release of players that support both, to be future-proof. While the X800M2 supports DV and HDR10, I do not think it supports HDR10+, but I might be mistaken. Of course, DV and HDR10+ make not a whit of difference for DVDs and HD Blu-rays, which do not encode HDR. The content, the player and the TV must all support HDR for it to provide a benefit.
Those of us, like me, who missed out on the Oppo UDP-205, may be tempted to rewrite the past by buying one of the US$1000 Panasonic DP-UB9000, the US$1000 Pioneer Elite UDP-LX500, and the GBP 2200 Pioneer Elite UDP-LX800 (the last apparently not for sale in the US). Per professional and user reviews, the video processing on these is said to rival or surpass that of the UDP-205, and one can tap the digital audio out to an audio system effectively as good as what the UDP-205 would give you. I forget whether all three of those players support both DV and HDR10+, or whether Panasonic and Pioneer plan to update the firmware to those capabilities. Availability of the Pioneer models seems low, so perhaps Pioneer is in the process of issuing revised models. Buying such an expensive player would perhaps be a last act of folly before resigning oneself to the inevitability of streamed content, of which the availability and particulars (example: bowdlerized versions) and cost can be variable for better or worse.