Could be X ammount of reasons why you don't get hired. Maybe client doesn't really care about his project, maybe job has too many applications and he doesn't bother looking past first 3 if he finds what he is looking for. Maybe he doesn't like your photo or maybe your country of residence. Maybe he is already interviewing somebody, maybe its just your competition trying to scan the market for prices or to steal portfolio pieces by posting fake jobs. Maybe your prices are too high (plenty of people here who want to get pixar level 10min lenght of animation for 1000 $ or less) or too low (yes for some people low price associaties with garbage quality), maybe your portfolio is not shinning and many many more.
For the most part you can forget about clients being objective. And treat this entire bidding thing as fishing, just keep casting your net and see what comes your way.
You could be world superstar level in your field making 10 000's of $ working in an office or anywhere else but once you come down to freelancing sites, prices drop. As freelancers are often viewed as cheap workforce for last minute projects. Upwork knows that thats why they charge 20% fees for projects up to 500 usd. Because thats absolute majory of them.
Reminds me of that Joshua Bell (grammy winning violin player) psichology study who played in the metro for 45min with his 3,5mil $ stradivarius and made 32$ tho not few days ago he sold out a theatre for 100$ per ticket. If you are serious about starting freelancing career well, prepare to bite the bullet for God knows how long.
