Idea: New unit type, amphibious

Or just blast yourself a safe zome with your navy and build vehicles on the shore?

Skip to a different planet, or even a small island on your water planet, get ground forces there, have navy clear a zone for a teleporter?

Turtle on your dominated ocean and get nukes to bomb the land till it glows, or.invest in orbital to get anchor offenses and laser sats?

Shove ground units farther and farther back with T2 navy and Holkins?

You have SO many more options than simply using air. Amphibious units are not needed to assault the land.

And if he's fortified the shoreline in such a way that building factories on the shore is not an option?

If it's a single planet system?

Turtling should not be the only option.

Holkins and T2 navy can only get you so far.

Well, everyone knows T2 navy needs a boost. Glass cannon boats are a serious issue, but once they're remedied then fighting from the water should not seem so hopeless as to warrant navy-replacing units.

But again; there are TONS of options for this scenario. Few players, if any, can maintain perfect combined coverage of anti-orbital, anti-nuke, anti-air and anti-naval/artillery defense for long. If you have allowed the game to reach a state where there are literally no options remaining, your opponent is keeping you alive for sport.