Because manufacturers like Specialized, Colnago and now Trek aren't producing their areo specific bikes anymore. They are now making 'all round' bikes, as it's much cheaper for them to produce one bike rather than have a climbing bike and areo bike. And you have all the media shilling and chatting BS about how fast they are, who are literally paid to promote them.
For example, the Specialized Venge that they stopped making in 2021 is faster than the current SL8, that's a fact. Likewise with the new Trek madone.
I had a modern bike, but sold it for a bike from 6 years ago, as it was noticeably slower and much higher maintenance.
Just my veiw as someone who's raced and worked with high end race bikes for over 20 years.