I see an extension of JBJ/Bogaerts/Betts highly unlikely. Our time is now, this team is in now mode....I say buy Strasburg next offseason and go for a run for the next few years.
With some luck in several years guys like Benintendi, Devers, Moncada, and Espinoza will fill the talent pool those guys leave behind (Price aging). And with some money freed up by then you can still probably extend at least one of those guys to a monster contract and maybe trade another to replenish the system.
Of course a lot can happen between now and then and this assumes a lot. I think any good long term plan is NOT a concrete long term plan. You have to be able adjust accordingly with the market, your team, and your system. Like for example, lets say all of a sudden the CHW want to trade a Chris Sale for a prospect heavy package to replenish their system (highly unlikely) perhaps you reconsider holding onto an Espinoza in a situation as such.