I started to write this as a reply to Felix's "Halcyon Years for phono cartridges?" thread, but decided to post anew so not to hijack his thread.
That thread inspired me to wondering how the state of record reproduction would have progressed had records and CD continue to co-exist, in the same way the records and cassettes once co-existed.
The expertise from the golden days of vinyl would have continued to develop and innovate, as technology, materials and manufacturing developed. Although this innovation in turntables, tonearms and cartridges has continued, in modern times it is very much development by boutiques, and is of much more limited scope. Even when there are examples of major companies who continued to invest in turntables (eg. Technics with the SL1200), there was less development (evidenced by models released) compared to the glory days.
A glimpse of innovation that did not continue was turntables which read records using a laser in place of a styli. From what I have read about the early, expensive prototypes and models is that this technology held great promise. Sure, they had limitations, but so did the early CD players which have developed in quantum leaps.
If the market for records wasn't killed by CDs would this technology (or other innovations) have become the gold standard for reproduction by now? Would you have expected it to be superior to digital? Would digital still hold dominance due to convenience?