And don't forget, Precure is actually the third show in the super hero time block, so it's not like Toei are unaware of the similarities.
Technically, Precure is the fourth show in the Asashi/Toei Kids Block, which basically consists of "Yearly Shounen anime", Super Sentai, Kamen Rider and Precure. So while technically Precure is not part of Super Hero Time, it does air right after it and if Toei one day makes it official an adds Precure to the SHT block, i will not be surprised.
But yeah, Toei is perfectly aware of the association between the three franchises, so much in fact that they have been using that relationship to promote the shows for years. For example...
...back in the year of 2006 Toei Bandai lauched this line of children´s pajamas of their three Super Hero franchises of that year: Boukenger, Kabuto and Pretty Cure Splash Star. They literally called it the "Henshin Suit and Dresses" line.
This goes back to the point i made before: Toei/Bandai does like to push Precure not as a Magical girl Franchise, but as a Super Hero franchise. For example, last year they aired the Super Hero Taisen Movie and the Precure All Stars New Stage movie back to back as part of their "Super Hero and Super Heroine Summer Special". Yes, that is how it was called.
My point is, Toei/Bandai does like to promote Precure as Super Heroes for girls, while it also promotes Kamen Rider as the Super Heroes for Boys and Super Sentai as the Super Heroes for everyone, essentially cornering the children´s market and often lumping together these three shows for marketing purposes (for example, the yearly precure season and the yearly Super Sentai season are usually announced in the same press meeting).
But going beyond what Clocktower said, yes, Precure is full of nods and in-jokes towards their "elder-brothers", and often times you will only get these jokes if you watch all three shows.
Also, there was that time that Cure Heart got married to Kamen Rider Wizard.