Well, racing once a week isn't done to boost iRating, it's done to achieve an artificially high championship position, which I've never been too fond of, but it is a severe limitation in the system at the moment. It never appealed to me anyway. If a track is fun I'll race until I get bored of it, on a track like LRP next week I might decide to race only once or twice though, since I just don't have a good time going around there.
However on the subject of inflating iRating... it's a bit of a misnomer actually. Once you go over a certain iRating barrier (which is around ~2300 I think) you will almost always end up in the top field. You'll never end up in a second tier field unless 12 people with higher iRatings have signed up, which rarely (~ never) happens with the current amount of subscribers unless the top drivers decide they want to have a battle royale or something.
So, if you can race in a competitive series and your iRating keeps going up, it's all fair game imo. The higher you go, the harder you get punished for a mistake, so you'll level out eventually unless your luck is endless - eg by having aliens crash out in front of you every single race. It currently takes me 3 wins/2nd places (in ~2200-2400 strength fields) to make up for a race where I crashed out and ended up 12th. If I can actually sustain that and my iRating keeps climbing, then I don't feel like I'm inflating anything really. Someone like Volker Hackmann pretty much
needs to win to gain iRating, if he's in an average field and ends up on the second step, then he'll actually even out in iRating, (last race on 2nd place in a ~2100 strength field, he gained 2 iRating
) does that mean his iRating is inflated? I don't believe it is, since he actually wins ~80% of his races right now.
It's a tricky subject, but iRating is not easy to inflate unless you can already win reliably. Championship points however, are quite easy, as all you need is one good race a week and for others to have one bad race a week. If people race regularly, that's almost always the case