Old iPhones unable to find wifi nework

My Dad has an iPhone 3g.

I have an original iPhone (2g)

Neither of them have the ability to find a wifi network anymore.

They have SIM cards in the, but the SIM cards are disabled (not activated by a carrier). Technically that should be unrelated, as they are different antennaes.

I am concerned Apple does this to all old phones to incentivise people to upgrade.

I've tried removing the SIM card as well, doesn't work.