It will be easier to buy accessories to help with loading the bike
Most improvement will come from battery suppliers, not bike manufacturers directly. Good news is that performance is steadily improving but the weight gain will be moderate.
For instance take Molicel batteries (that Stark is using), they went from 4.2 Ah P42A cells in the 2022 6 kWh prototype to 4.5 Ah P45B cells in the 2023 6.5 kWh production bike. Now their newest 5.0 Ah P50B cell is slated for mass production later this year. That could mean capacity going from 6.0 to 6.5 and 7.0 kWh (if Stark were to adopt P50B) in a couple of years. Or even up to 7.2 kWh for an extra 800 g. In my opinion they will first focus on getting up to a target capacity (say 8 kWh) before further performance gains could go towards lightening the pack.
Flux is aiming for 7.9 kWh so any improvement in battery performance could possibly be used to lose weight instead of increasing capacity.
Maybe some manufacturers, or aftermarket suppliers, could offer some lighter batteries with limited capacity but honestly I'm not sure if that would be so popular?
At one point we'll get to hybrid then solid state batteries, weight loss could be more significant, but that won't be too soon so don't pin all your hopes on this
.