I think they do whatever the can to keep him but they are set up for a 2019 mid season or 2020 sell off as well. 2 years $70M for Scherzer with no options isn't insane to move if he keeps pitching well, and Strasburg would be 32 and have only 3 years $55M left making him a very valuable trade chip. A healthy Adam Eaton could be a huge trade chip as a 32 year old with 1 year $1.5M and two $10M options.
I think they will start to concentrate on extending Rendon and Trea Turner if Harper doesn't sign. If not Rendon would be a mid 2019 trade chip as well.
Mike Rizzo doesn't do a lot well, but payroll management has been better than you figure.