Hey! I haven't been checking itchio and only now see this post. Sad to hear you thinking about dropping this, but I do understand where you are coming at.
I would buy the full game for any price, online or not. Just singleplayer and Local (and LAN??) would be so great. There are no modern or good hoverbike games (execpt Desert Child but that's really different) and therefore I really think this game has potential to be commercial success, if media picks it up, etc. There are not good jousting games either! ;)
Just doing DM in current build is so much fun. I think this could be really cool even without online MP, just need to make the single-player aspect appealing, really come up with something cool. For example (most obvious that come to mind) proper and challenging, championship mode, and some sort of trial mode (race to finish or JOUST all the targets).
I can see this game going in many directions, the DM jousting aspect is great ofc, or make the physics and controls more finesse and challenging-> racing becomes more interesting itself. As of now, the physics and controls are IMO such that they support the DM aspect much better than races, although races are still also very fun!
Honestly, I don't find CTF as a very intriguing mode for this game. Maybe some sort of sport involving a ball and goals...? Meh..?
Aforementioned trial mode, navigate hard tracks (+track editor??). This could even work as a exploration game, could be fun to explore vast open map with the bike, hard places to reach, with some gangs that you have to beat (Deathmatches and races). maybe get some upgrades and able to tune your bike (cosmetics and performance). Or take influence from kart racers, take the best of mariokart/CTR and put it there. Maybe a track editor that allows custom objectives (race, find all objects, tip over all barrels, kill x amount of opponents, race under xx.time). Make local-co-op interesting somehow, some challenges, chase (try to KO other, other tries to run), team chase, tow some sort of barrel and protect it as team from enemies. Some sort of infinite mode would be cool, be a team, see how long you survive, how many opponents you can joust.
Just what I mean with these good and awful ideas is that in my eyes this has great potential to go in multiple directions and to be a great game even without online. Thinking about commercial success, even with online emphasis it might be really hard because getting a good/big enough community is really hard and you get negative reviews for just if there are no people online playing it.
I really hope you will make at least some sort of completed game out of it! I promise I will buy it :)