8 years is indeed a long time, but it could go by pretty quickly. For example, at DHS...
- Mid 2019 - Opening
- Late 2019 - ROTR Opening
- 2020 - Park operates with full functionality for the year
- 2021 - Star Wars Hotel opens, new Smuggler's Run mission becomes available, construction begins on Cantina expansion
- 2022 - Cantina expansion opens
- 2023 - Final Smuggler's Run mission becomes available
- 2024 - Announcement of expansion, some sort of tie-in with the 2024 Star Wars release
- 2025 - Construction on expansion begins
- 2026 - More cross promotion/tie-in with 2026 Star Wars release
- 2027 - Expansion opens
This is obviously just spit-balling, no inside information is informing these dates. But it illustrates that 8 years isn't that long, if the 2027 date is indeed correct.