Oh, I don’t see them either now that you mention it
Sumo being dropped would be quite shocking as it was routinely one of the most popular sports. I believe it sold out of tickets for multiple editions of The World Games. It was certainly the hottest ticket last summer as least. Of course, there was also that dramatic disqualification/re-match episode last year too.
Bowling being dropped wouldn’t be as big of a surprise to me. It’s not the most television friendly sport, though it certainly can be broadcast and easily followed with decent graphics. It also has a semi-costly, specialized venue that can’t shared with other sports on the program. Still, it would be tough to see such a mainstay booted off the program.
EDIT: I forgot when I wrote this, but the IBF (International Bowling Federation) was embroiled in a financial/governance scandal recently. Link: https://www.insidethegames.biz/articles/1123554/ibf-financial-allegations-on-eve-of-egm
The gold medalist in women’s singles at The World Games 2017 was also disqualified for doping, so maybe a combination a strikes against the sport.