They also bought Ronaldo and are trying to buy De Ligt / Umtiti as well as being linked with lots of other players. I suppose being the only big club in Italy helps.
They signed Ronaldo for 100M and are paying him massive wages. To sign Felix should be doable for them just about. But to add De Ligt as well is only happening if they make a massive sale. Serie A just doesn't generate those sorts of funds from TV revenue, and their stadium is about 44K, and not always a sell out. Plus ticket prices are lower than in the PL. They are hugely reliant on CL revenue to stay in line with FFP. I could easily see them selling Sandro and Dybala. Umtiti seems a feasible signing, as he'll probably cost 50M. Felix will comfortably cost 80M+ given the level of interest in him.
It's also worth noting that Ronaldo is on 30M a season in wages. That is 625K a week. Just a quick note on the maths. One doesn't divide 30M by 52 weeks, as is often seen on the forums. Pay periods are typically split into 24 semi-monthly checks. Meaning the year is split up into 48 "weeks", as each pay period is covers a little over two weeks.
Those are massive wages for a club with Juve's turnover. He's also on a 4 year contract. and is 34. I don't care how good he is. He's 34. His influence is only going to wane. If we amortize his transfer fee over the course of his contract, and add his wages, his cost to the club is 1.146M a week. This is a lot of money. And while obviously fine when he is still performing as he is, - and hugely marketable, it stills seems a frightening amount to pay a 36-38 year old (which he will be in the final two years of his contract). There's a reason Real were ready to get rid. And even though they've had a tough year, that was ultimately brilliant business for them in the long term.
Time will tell how much this impacts Juve in the transfer market.