The Pro Series is obviously targeted at the higher-end markets. Samsung's second-generation TLC-based SSDs, or the third ones, do not have to be slower than 840 Pro. I have no more solid data on the endurance or longevity or MTBF or whatever it is of all the drives based on SLC, MLC, and TLC. What I know for very sure is most people were against the switch from SLC to MLC for years. Many of those waited years while most newcomers chose much cheaper MLC drives without ever using SLC ones.
What most reviewers and end users have said on the life cycles of SLC and MLC chips were not based on experiences or hard science, but on whether one first chose to believe FACT X popularized by some seemingly highly knowledgeable person.
The Tech Report reviewer wrote a fine review of one of Samsung's latest SSD product. Anandtech's Anand has posted a few good ones. But the overall quality of the various reviews is too low, low enough that I say there's little sense in anything. I have had deeper trust in what the managers and engineers at Samsung and Toshiba have said, and they mostly proved to be correct. But then humans cannot compete with the rate of social progress lead by technologies that in turn are discovered by themselves. It is often impractical and impossible to expect for the average humans to observe the long-term impact of technological inventions and products on the societies in fairness.
It would have been a much different story if it were Intel or Micron instead of Samsung that lead the massive and bold proliferation of SLC chip-based SSD drives in the mid-1990s. It was a very significant change, but was not discussed significantly enough on most English-language technology websites. Again, the arrival of nearly cheapest SSD drives utilizing one of the latest fabrication processes cannot be interpreted as a progress because it's by Samsung. It has nearly always been the same with Samsung-made optical disk drives.
Sometimes I feel Oriental languages and characters are savage. Sometimes I feel Western languages are retarded and make retarded people, but that's something I'll have to talk about in another space.
To answer the question, there is no reason I can think of why Samsung cannot release, either to retail or OEM, something that is both cheaper and faster than 840 Pro and it should have been clear it costs less for Samsung to make cheap and fast TLC drives than to make existing MLC drives cheaper in the first place since that was exactly why they chose to increase the share of MLC chips years ago and then that of TLC chips in more recent years.
Samsung did not start any "hyping" of the 840 Series drives. The unofficial, independent review performance scores are not that different from the official specifications. The non-Pro 840 Series products are actually fast and cheap drives. Millions of consumers once paid nearly same for SLC and MLC drives. That was when most experts were saying SLC is 1,000 percent more reliable than MLC, or the former lasts 10 times longer than the latter. You now have an opportunity to buy fast enough drives at something like 50% lower prices than MLC counterparts.