Momota and Srikanth -- who have played each other 15 times, with the Japanese player winning 12 games -- were set to clash on Wednesday, but there was no indication why he had withdrawn from his first match.
Home hope Chen Yufei similarly successfully defended the women's title with a gritty victory over Japan's Nozomi Okuhara.
The title-holder brushed aside Denmark's unseeded Ramus Gemke 21-19, 21-8 and faces Taiwan's world number two Chou Tien-chen in Sunday's championship decider.
World number one Momota will play Axelsen's fellow Dane Rasmus Gemke or Hong Kong's Angus Ng Ka-long in the last four on Saturday.
Chinese media have speculated that Lin Dan could announce his retirement imminently.
13-year-old Sanjana C Upadhya of Noble International School won the Girls Under-17 by beating Pavithra Shetty 21-12, 21-14 in final.
The 25-year-old downed Chou 21-19, 21-17 in a final that lasted 53 minutes.
The 24-year-old thrashed Japan's Nozomi Okuhara 21-7, 21-7 in Sunday's women's singles final.
The World Championships will be held in the Swiss city of Basel between August 19-25.
Momota and Akane Yamaguchi gave Japan their first ever sweep of the men's and women's singles titles on Sunday, raising Japanese hopes a year out from the 2020 Games.
Yamaguchi, who is ranked world number four, defeated an out-of-sorts Tai 21-9, 21-15 in a little over 30 minutes at Jakarta's Istora Senayan Stadium.
The duo reigned over the sport for more than a decade and have only relinquished that hold in recent years as their powers waned.
Lee, who spent a total of 348 weeks as world number one but lost six world and Olympic finals, wept as he called it quits months after fighting off nose cancer.
The comfortable 3-0 victory sets China up for a tournament decider against top seeds Japan or Indonesia, who play their semifinal later on Saturday.
Thailand will play hosts and hot favourites China in the last four of badminton's prestigious mixed-team world championship in Nanning.