It is very likely they're considering not droppping an announcement on a lesser known hero product (regardless of how well early access reception to the film is) in the start of the merch push for arguably the biggest superhero event ever. Especially when the wide audience both in the US and China haven't seen Shazam yet. That's product advertising suicide.
Marvel makes bank. DC is playing catch up and patching their wounds still. Suicide Squad, Wonder Woman, and Justice League all have products that are still available for retail. I'm gonna be real curious to see how the Aquaman figs do, as it seems like the merchandise for the film largely sunk hard all around. Most Marvel releases are selling out. If I were a business, I'd divert the vast majority of my talent to the licenses that bring in the most revenue, then fill in the gaps. Especially when that license is currently going through a historic moment that very likely won't be repeated in our lifetime.
If Shazam is as well received as the early showings seem to imply, then I am sure we will see a figure from HT. They have the DC license, Warner just needs to prove they should do it.