That's not it at all. It's not about power. It's about control. I mean, I'd be fine playing a wizard who could only cast one spell per day, or even one spell per week, as long as I have some control over when I get my slot back. I know what I need to do in order to get that slot back, and I can take that information into consideration, so it feels like my decision is meaningful.
Last I checked, it takes something like 13 encounters to gain a level (for certain levels). Assuming 5 encounters per day, that makes 2-3 full adventuring days between levels. In practice, a wizard ends up casting about two spells per encounter, or about 25 spells between levelling up.
You could give the wizard 50 spell slots per level-up, such that they can safely cast four spells per encounter, and it still wouldn't feel good to play a wizard. You still aren't making an informed decision about when to spend your resources. If you take it on faith that you'll gain a level when you need it, then it might be kind of fun to go all-out and dominate every encounter, but that would get old fast (especially for the martial types). Assuming you want the game to maintain some semblance of balance, then this house rule is just sacrificing the wizard's control over their own future, for no real benefit to anyone at the table.
A better rule would be to reduce the spell slots per day, but give casters a way to actively recover spell slots that doesn't depend on DM fiat. Off the top of my head, you could give them an action to steal mana from enemies in combat, or capture the life energy from a dying monster, as examples. That way, they can't just get their spells back whenever they want, and they need to engage with the adventure (beyond just casting spells to solve all of their problems), but they still have some control over replenishing their resources. You never end up with some burned-out wizard who is incapable of going on adventures because they ran out of spells twenty years ago.