I tend to dislike arbitrary loss of ability, especially when it happens because I have leveled up. If you have to cut abilities out of the player to force them to upgrade their tools, you are punishing them for leveling and introducing a mandatory tax on their accomplishments.
This would be like getting level 5 in world of warcraft as a mage and the game saying "Well you have outleveled your firebolt spell so it's now only 50% as effective as it was before and you will have to spend money to upgrade it to normal again." This leaves a bad taste in a player's mouth, and makes no logical sense. I have become a better mage, why do I now cast firebolt so shitty? Why does paying money restore it to normal?
Instead, World of Warcraft says "You are now level 5. You can upgrade to Firebolt rank 2 which will give you more damage and will be more effective against monsters of your level. If you use the old firebolt against new monsters it will be resisted more often and do less damage." So you keep your firebolt spell but it won't work well on new content.
In your case, it is like the game saying "Congrats, you are level 5! You have decided to throw away your super useful grappling hook because it was dirty and level 5 people don't use dirty tools. Also your antigrav pack broke because we don't like you. Go buy new ones, you silly level 5 guy." if you're requiring a player to spend X amount of money/resources to maintain their current capabilities you may as well just make money/resources less common so they never get that X amount and then let them keep the capability. You've introduced a tax on accomplishment which adds no fun and exists only to remove money/resources from the player.
(Again I have not yet played the game, these are just my thoughts in general. I will be trying it out when I get home, I'm still at work at the moment.)