Does it not defeat the object to have those players within a week of the game launching, though? It might cost a lot to pay all their wages but you can rotate your elite players around and keep a still-amazing squad going week after week.
There is no "working up from the bottom" any more in football games. The old FUT system used to let you play in bronze, silver and gold cups - so you didn't have to play a team better than Real Madrid on day one. But that doesn't exist now.
Before your first ball is kicked, you're in charge of a Champions League side.
Some of the pre-order bonuses, top agents or in-game rewards (like promotion in online divisions) give you "contract renewal tickets" which renew any player's contract for 10 games. Currently I have 30 of these (never used one)...
So you could use those on your very highest rated players that would cost 3-4k to renew and get cheaper gold players to make a top quality team somewhat sustainable for a while, though if you play enough games (and lose plenty of them) you'll run out of those tickets... And then the easiest way to continue would be to buy contracts for coins...
OR, and this seems to be the popular way (at least on /r/WEPES), you "farm" GP by playing/simming hundreds of matches with a white ball/black bench team. This gives you maybe 2-3k GP profit per match, but seems to be an extremely tedious and ridiculous thing to do in a football game.
Yet the thing is, those people actually welcome it! For them, the "grind" is half of the fun... Just look at the /r/WEPES subreddit occasionally, the FIFA one too... The vast majority of the discussion is related to MyClub/FUT, and anyone who criticises the modes is downvoted to oblivion and told stuff like "it's my money/time, I'll spend it how I like!".
I hardly blame Konami/EA for pushing these modes so heavily and neglecting everything else... The community at large has actively decided, of their own volition, to make them the most played game modes.
Our only hope seems to be that the authorities in more countries will grow some balls and put some legislation/ban on this kind of shit, like Belgium seem to be doing.