Knowing that you will hit the limit of the database in X years is different.
Designing for the future is a horrible choice because where do you stop?
Eg. Why are you sure that Cassandra, or whatever you choose, will be good enough for the future? Maybe you will need a Spanner type database or something even more big/consistent/feature-full.
Based on what ? There is no evidence or logic behind this.
If you know that you are producing say 1GB a day of data that you must store then it is sensible and prudent to select a technology that can support your needs a year or two from now.
And this idea that you always have resources to make a switch later on is rarely the case. The more common scenario is that a team is established to implement something, it moves into production and then the team either disbands or moves onto something else. Why do you think so many people try and plan for the future ?
In most enterprise companies at least it would be considered a failure to have a project that in a year's time required another business case just to replace the database that the team should've appropriately selected in the first place.