Ice boats and elytras should be nerfed in the nether

With the new minecart changes, there's been a renewed interest in making railways a good mode of transportation. And while that's good, I don't think they'll ever be used properly while ice boats and elytras are unchanged. Ice boats will always be cheaper and still very fast, and elytras make infrastructure redundant. However, I don't think you can really nerf either of them (other than small speed changes) without a lot of people getting angry. Therefore, I think a good balance would be to make them useless for nether travel, so that minecarts can once again become useful for long distance travel. To do this, I propose two changes. One, either packed ice and blue ice melt in the nether, or boats travel at the same speed they do on water when in the nether. Two, fireworks will always do damage when fired in the nether, regardless of type. That way, both features can be used in the overworld as normal, but aren't useful for long distance travel in the nether. Both are fast enough, and don't need an 8 times multiplier. Coupled with some minecart improvements like greater speed and the ability to travel through nether portals, minecarts would once again be useful for long distances. Which I think is fair, because they have quite an upfront cost. For context, ice boats travel at 40 blocks per second on packed ice, and 72 blocks per second on blue ice, while elytras travel around 30-40 blocks per second at a roughly horizontal pitch. Having minecarts travel at 8 blocks per second is rubbish. Just this change alone will make them on par with overworld ice boats in effective speed, while a boost to 20 blocks per second will make them the fastest option in the game, while not ludicrous.