Vertonghen will be 33 when his contract expires at the end of the season, so nothing odd or unusual there. Very few european level teams will offer extensions to players of that age until a lot closer to the end of their contract.
Alderweireld has been known and expected for a few years and he wouldn't extend (apparently) due to Poch, and he's now suggesting he might extend.
Eriksen is now so incredibly cack that he's neither a first choice player, nor an issue to replace. Lo Celso was bought to replace him ahead of time, so not really an issue at all.
Wanyama and Rose both have until the end of next season, with the former being all but gone already anyway as he's a permacrock. Skipp has replaced him for all intents, so not really a drama there either. We need to look at full-backs for sure, maybe bin off Lloris finally, but that's no different than City or Liverpool have done in recent seasons to great success.