If we honestly think it's unrealistic for a guy like Ian to get a girl like Lena we are way too far into delusion land. Ignoring the fact that conventionally unattractive guys get with conventionally attractive women all the time. Ian, who is pretty conventionally attractive, at the start of the game before player input magic, is physically fit, highly social, shares common interest with Lena, and is presented as a very respectable man. This already puts him ahead of the vast majority of men.
Generally speaking he already meets most women's generic requirements. The only way other men can compete is if they have a similar (or better, which is uncommon) portfolio or the women have a different aesthetic preference, a specific fetish (like Lena on the BBC route), or want a rich man. All of which are superficial preferences that Lena, at the start of the game, does not have.
If you're a man and look at Ian and Lena and think that would never happen because Ian is unattractive and Lena is attractive. Congratulations, you're straight and not attracted to Ian. However, plenty of women would go for a guy like Ian and do so all the time. The world isn't like the fantasy sold to you in redpill podcasts where only the top 1% man who is the most ripped and richest can attract beautiful women.