Pawns just serve a different function in these games. In Chess they are used to build a protective wall. In Xiangqi they are totally useless for that, and their function is to storm the enemy Palace, to trade away the Palace Guards and Elephants. Shogi is hard to compare, because of the drops. I guess the most important function of Pawns there is to occupy space in order to prevent the opponent from dropping material there. (And of course to drop and promote them behind enemy lines, to trade for stronger pieces.) Protective walls do not offer much protection in Shogi, as you just drop material behind them.
To judge how the Asian Pawn would function in a closed rank in absence of drops, one should look at Chu Shogi (the ancient Japanese 12x12 game). There one does use the Pawns in protective walls, but in combination with the lighter generals (like Copper) directly behind them, protecting 3 Pawns.
I've been getting into the other board games descended from the Indian game lately like Xiangqi (Chinese) Shogi (Japanese) and Makruk (Thai). All three have their interesting aspects and differ significantly from Western chess. One thing I have felt, partcularly with the Chinese and Japanese forms is that the pieces do not feel as co-ordinated as they do in western chess. This is emphasised by the fact that the pawns capture forwards and therefore cannot defend eachother - so you don't get the sense that pawns are worth more than the sum of their parts like you do in western chess. Makruk feels more like a complex endgame since its similar to chess but with underpowered pieces.
I was wondering if my feelings about these games are due to inexperience or if people who have more experience with more than one of these games feels similarly.