I took a look at the Rams roster a few months ago, when Woods and Kupp signed their extensions. What I found dovetails nicely with your analysis.
Seeing Kupp and Woods sign extensions that run thru the 2023 and 2025 seasons respectively I wondered if there was any evidence of a long term plan. Here's what I found:
Thru the 2022 season the Rams have 10 of their current starters signed. The exceptions (and the potential replacements who are already signed thru 2022):
Blythe
Corbett (Anchrum, Edwards)
Noteboom (Evans)
Reynolds (Jefferson, Jackson)
Brown (Akers, Calais, Henderson, Jones)
Joseph-Day (Gaines)
Ebukam
Floyd (Lewis)
Kiser (Hollins)
Reeder
Hill
Johnson (Burgess, Fuller, Scott)
To me it looks like the Rams have successor plans for everyone except Blythe, Ebukam, Reeder, and Hill. The 2021 draft is when the Rams would draft potential replacements and/or depth with 2022 in mind ...
... or maybe they just promote some guys from their practice squad (Cabral, Bituli, Patrick, Rozeboom, Moncrief, Deayon, McGee, Hughes, Reed) ...
... or perhaps even resign some of their less expensive FAs over the next 2 years (Blythe, Fox, Ebukam, Shelton, Williams, Howard, Corbett, Allen, Young, Polite, Kiser, Okoronkwo, Reeder).
In short, it does look like there's a plan and IMO it looks like it's playing out well.
AlbaNY_Ram