I wouldn't go that far... IMO RCT2 has been the best game in the franchise, with the most replay-ability. Frontier did a pretty good job on RCT3, but they were seriously limited by funding from Atari. Atari effectively killed RCT3 with cutbacks and rushing development. RCT3 was released buggy, never fully fixed, and never fully optimized. Even on powerful machines today that laugh at high end games, RCT3 can bog down and have issues with graphics.
Planet Coaster is more or less a lesson learned. Frontier is no longer at the mercy of Atari, they have free reign to control all aspects of the development process and as such are making a FAR superior product. This is extremely evident when you play RCTW and then switch to PC. The difference in quality is absolute night and day.
To me, Planet Coaster is the true evolution and follow up to RCT3 as it holds onto the fun loving environment and creative playground that Chris Sawyer introduced with RCT1. Being someone that has grown up with the RCT series playing RCT1 from day 1 of launch, I can truly say that I am so happy with Planet Coaster and so incredibly thankful to Frontier for giving me a piece of my childhood back at age 30.
I would also like to point out from the horrid comparison video, solely based on the voice of the creator, was this person even alive when RCT1 came out??? [bored]