If the Shows series had continued?

It would have had to come to an end sooner or later, each of Japan's empires changed which is why it went from showa to heisie, it was due to the rule of the new emperor.

Although, if the series continued i would still be happy with it, the showa era has the best godzilla films to date in it, and GMK could have been one of them had shusuke kaneko got work with TOHO earlier.

The style simply would've shifted and evolved much as it did from the 50s to 60s and 60s to 70s. I imagine the atmosphere of the storylines might have gotten more "serious" like the Heisei series, but simply woven into the same timeline.