playshin, I know exactly what you mean. But my counter example would be that, if people login to LOL, they're probably gonna play a game anyways. I mean how many times have you finished a game with a victory and see that it says "First Win of the Day Bonus Available" or have it read ~3-10 minutes before its available? Its not a big hassle, or anything, just a convenience. Even if there was like 25 min before the first win bonus was available, people could still start games because most games take longer than 25 minutes anyways.
Besides, what wrong with people only playing the 1st win of the day games? Some people are busy and only have time to get one game in, might as well make it the 1st win of the day game. As an actual problem of having less players online? That might be a minor issue, but RIOT doesn't make money for people being online, I don't think so anyways. They get money from the microtransactions when people buy RIOT points, which are used for buying skins, or champions. So if someone is going to buy a skin, they're not going to just going to play one game, they're going to want to show off that new skin.