Every year there is a push to buy new clothes on Eid, references?
Short answer: No it isn't.
Nevertheless it is highly recommended to wear the best of your clothes in such occasions and this actually has backup in the sunnah. And in some cases this may mean that one ought to buy new clothes.
'Umar saw a silken cloak being sold in the market and he brought it to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! Buy this cloak and adorn yourself with it on the 'Id festivals and on meeting the delegations." Allah's Messenger (ﷺ) replied, "This is the dress for the one who will have no share in the Hereafter (or, this is worn by one who will have no share in the Hereafter)." After sometime had passed, Allah's Messenger (ﷺ) sent a silken cloak to 'Umar. 'Umar took it and brought it to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! You have said that this is the dress of that who will have no share in the Hereafter (or, this is worn by one who will have no share in the Hereafter), yet you have sent me this!" The Prophet (ﷺ) said," I have sent it) so that you may sell it or fulfill with it some of your needs."
(See for example Sahih al-Bukhari, Sahig Muslim, al-Muwatta' and elsewhere)
Why this hadith is used as an evidence? First of all the prophet () did not reject the idea of wearing good clothes, but he rejected them as they were of silk and silk is haram for men to wear. That's why scholars concluded, that wearing your best clothes -as far as they were not of silk- is recommended on 'Id, as the prophet () here only rejected the kind of clothes not the idea of wearing the best you have of them.
As-Sindi said in his commentary on an-Nasaa’i (3/181):
From this it is known that adorning oneself on the day of Eid was a tradition that was approved of among them, and the Prophet (blessings and peace of Allah be upon him) did not object to it, thus it is known that this tradition is valid and continued. End quote.
(Source: islamqa fatwa #144885)
The quoted part is not really of value, but the link was very helpful(though I have to be careful with any "fatwa")– GosejokJun 17, 2021 at 11:11