"Despite these issues, Regan is confident that by investigating black holes in the early universe and by potentially discovering heavy seeds, scientists will soon be able to build a supermassive black hole growth picture. In particular, he pointed to the launch of the Laser Interferometer Space Based Antenna (LISA), a space-based gravitational wave detector that will help scientists better constrain the demographics of black holes in the early universe. "I think we made a huge amount of progress in the last 10 years. Huge. And we will continue to make massive progress over the next decade as well.," Regan said." Extrapolating out from these demographics will give us a very, very good handle on the number of mergers happening in the distant universe involving black holes in exactly the mass range we need, with masses around 100,000 times that of the sun. "I think it is very probable we will have solved this problem in the next 5 to 10 years."
My observation. I am not so sure about this, *I think we made a huge amount of progress* concerning the origin of various SMBH documented now. Space.com reports recently also show Population III stars as possible seeds, some 1,000 to 10,000 solar masses or more. Other reports on inflation, in the post-inflation epoch can create a plethora of PBH, primordial black holes that could fill the universe today, and if they grew over postulated billions of years after the postulated BB event, could be very big today