Has any science fiction writer ever announced that he or she has given up writing in that genre because technological progress has pretty much ended?

Charlie Stross has expressed disappointment that technological change hasn't been as rapid as he hoped for in the mid 1990s, but that's a very different claim. I don't think anyone has claimed that progress has stopped completely, and it would be very strange to do so. Yes, the specific technologies involved in space travel have not progressed much but even in those areas progress is still occurring: the rise of cubesats and private rockets, the spread of highly accurate civilian GPS, the ability to send long-lived rovers to other planets - these are all advances in the last 20 years.

Outside space issues, there's been big jumps in technology- the most obvious changes have been (and continue to be) in the computer related fields (e.g. cheap smart phones, rise of big data, general increase in computer power level, drastic reductions in bandwith cost) but there have also been major improvements in other fields.

Let's look at medicine. HIV used to be a death sentence and now the life expectancy of people in much of the developed world with HIV is close to that of the general population. Death rates from various cancers continue to decline. Many tests are faster and more reliable. You seem implicitly to be using a 45 year time window, but in either a 45 or a 20 year time window, these advances are pretty clearcut.

I could continue with other fields but the general trend is clear: progress may be occurring slowly but technological progress is still definitely going on.