If MicroLED can be made in a cost effective manner and live up to its potential, then I agree it absolutely should be the preferred display tech. But, it's not a given that will happen. Pixel density is an R&D headache right now. Getting the pixel density down to where it can accommodate enough pixels for a 4K display (especially 8K) at 55" inches has been in a word challenging. Do I think it will get there? Yes, eventually, but it aint gonna be tomorrow. It's also important to note that while sharing a similar name, MicroLED is in many ways different from current LED, so it's not a proven that it will be able to carry all the advantages of LED and negate the disadvantages. It should mind you.
As for killing OLED, I don't think that will happen as OLED still has plenty of things going for it. OLEDs pixel response time is the best of all display tech, an advantage that often gets ignored since it's not in gaming monitors. If they can get OLEDs size down it could make for a very competitive gaming monitor.
OLED tech continues to evolve and get better and many of the anti-burn in features go a long way to minimizing OLEDs biggest concern.
Another advantage is that cost of OLEDs continues to go down. By the time MicroLED makes its way into stores, it will definitely be priced in the premium price of around $2500 - $5000+ By that time OLEDs could potentially be had for well under $1000. OLED still has good life left.