>>23371732
>birthrate in japan is declining with less kids to buy toys, so they aim for a wider market
Zero-One is the second best selling season and that wasn't too long ago, Gotchard was last year and it almost reach Build levels of sales, Gavv's problems with its sales are underproduction and Japan's declining birth rate isn't as bad as other Asian countries. Kamen Rider continues to be one of the most financially successful franchises that Toei has ever made, most of Disney's IPs are bleeding money due to how mismanaged they're right now, weird Japanese shit continues to get official subs in the west anyway and the main goal for Toei will always be the Asian market.
Just because this season is catering to the west to ease new fans in it doesn't mean this will become the norm from now on. As always wether we get something whacky or not depends on the producer.

>>23339607
Zi-O has the highest-selling toyline in the franchise.

>>23317445
The first DVD volume, which came out in August 3rd, had the highest sales in the history of Heisei Rider. Toy-sales wise, the first and second quarters were slight improvement from Kabuto's, while in the 3rd and 4th it made more than double the numbers of the previous year. CD sales were also strong, the first OST CD came out on June 27, 2007. In January 2008, the series won the Kurata Masumi Award at the Japan Otaku Awards 2007 (the decisive factor in winning the award was that it attracted the attention of female otaku).

So basically Den-O was a proven success by the second half of its run, dunno when the character merch started to blow up though.