The claim that today's songs are becoming shorter due to TikTok is mostly accurate. Due to the rise of streaming platforms such as TikTok and Instagram, songs that are quick to grab viewers attention, with a memorable line or beat, are bound to go more viral. This new way of enjoying music required less attention to length and depth, adding a heavier emphasis on a quick hook and a catchy chorus. According to BBC News, the average song length in the late 2010’s dropped to just over 3 minutes, directly correlating to the reward of higher play counts and the popularity of songs that quickly attract viewers on streaming services. This was also seen when analyzing more recent song structures; intros have become shorter, hooks now hit earlier, and bridges and outros have been shortened, if not cut out entirely. However, it is important to note that several other factors play into song length, such as genre trends, cultural attention span shifts, etc. To add, this trend is slowly ending, with statistics pointing towards a slight uptick in longer length, more unique/personal songs. People are once again beginning to enjoy longer length melodies, especially if they address important topics.
https://www.bbc.co.uk/news/resources/idt-052ab668-403d-416f-b5a6-c5692313b9b4