This sums it up very nicely.
The Blues core is Tarasenko (24), Schwartz (24), Fabbri (20), Pietrangelo (26), Parayko (23) and Allen (26). Throw a couple vets like Stastny (30) and hopefully Steen (32) in there, and that's what the Blues will be competing for a Cup with over the next 5 years. That's a good young core, and they need to win a Cup with them.
They will likely need to add a young top 6 center to that group, but hopefully with this low cap hit for Schwartz, letting Backes go, probably trading Shattenkirk, they will have some added flexibility to do that and pay that player as well.
6-7 years would have been nice, but getting Schwartz for that cost at that term was simply unrealistic. He will get a bigger payday at age 29. Works for both sides.