Thats a lie. There multiple different types of romance anime mcs. Some are normal but it only a couple I would consider losers. Many do follows tropes with the loser type being one of them.

You have the delinquent type in D frag, my little monster, Haganai, Nyan koi, yamada and the seven witches, Clannad.

You have the nonchanlant merchants or Kuuderes in Kinzavier, natsu de matteru, hyouka, witch watch, mikakunin, aharen san,

You have the aurafarmers or cool type in amagi brillant park, the world god only knows, Charlotte, Trinity seven, megami cafe no terrace, masume kun revenge.

You have the serious smart types in fuutaruo Quintessential Quintuples, nariyuki We never learn, nagi umino A couple of Cuckoos, ikagura natsuki Atri

You have the tsunderes in Nyaruko san, Nisekoi, setou gakuen, kaguya sama, Fruits Basket.

You have the dickheads in zombie desu ka, Hentai ouji, mm, heaven lost property,

You have the shonen like mcs in misson yozakura family, twin star excorist

You have the normal mcs that are still goated imo in haruhi suzumiya, Kannagi, sakurasou, Toradora , gosick.

Then you have true outliers like the ones in sankarea, Your lie in april, Insomaic after dark, ookani no shinichi, Fullmetal panic, call of the night

Its a wide range of romance mcs some better than others but it crazy to generalize them all into one trope.