The best replacement for snowshoes is skis.

The best alternatives to snowshoes are rated as following:
★★★★★  skis
★★★★  crampons
★★★★  cross country skis
★★★  splitboard
★  microspikes
★  atlas

Your alternative for snowshoes is not listed? Suggest!
Speaking about snowshoes, one probably shouldn't forget about ski boots.

Other search terms related to snowshoes and their ratings are:
★★★★★ ski boots
★★★★ snowboard boots
You have in mind a companion for snowshoes and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of snowshoes in all years. Click on graph for more.
snowshoes
skis
crampons