Customs and traditions are the integral part of every Sanatani. This was never be classified under oppression or monopoly as viewed by alien lenses.
All those who will not follow traditions will be punished?
As per Dharma shastras, Yes!
Thus, coming to various shastra pramanas why one is ought to follow customs & traditions,
Vamana Purana, Chapter 15 Pulastya Maharishi explains this to Sukeshi.
....यो हापयति तस्यासौ परिकुप्यति भास्करः।।
He mours the wrath of Surya, who forsakes the duties.
कुपितः कुलनाशाय ईश्वरो रोगवृद्धये।
भानुर्षे यतते तस्य नरस्य क्षणदाचर।।
The offended Surya strives to destroy his family and subjects, him to increased diseases, O demon.
तस्मात स्वधर्म न हि संत्यजेत न हापयेच्चापि हि नात्मवंशम्।
यः संत्यजेच्चापि निजं हि धर्मं तस्मै प्रकृप्यते दिवाकरसतु।।
Therefore one must never renounce his Dharma, nor should he bring the destruction of about his own family. On him Surya becomes angry who abandons his duties.
Gītā 1.40 says,
कुलक्षये प्रणश्यन्ति कुलधर्माः सनातनाः।
धर्मे नष्टे कुलं कृत्स्नमधर्मोऽभिभवत्युत।।
In the destruction of a family, the immemorial religious rites of that family perish; on the destruction of spirituality, impiety, indeed, overcomes the whole family.
Kulaskhay, also means destruction of family traditions.
Now what are the outcomes of bringing end to family traditions are again said in Geeta.
अधर्माभिभवात्कृष्ण प्रदुष्यन्ति कुलस्त्रिय: |
स्त्रीषु दुष्टासु वार्ष्णेय जायते वर्णसङ्कर: ||
With the preponderance of vice, O Krishna, the women of the family become immoral; and from the immorality of women, O descendent of Vrishni, unwanted progeny are born.
सङ्करो नरकायैव कुलघ्नानां कुलस्य च |
पतन्ति पितरो ह्येषां लुप्तपिण्डोदकक्रिया:।।
An increase in unwanted children results in hellish life both for the family and for those who destroy the family. Deprived of sacrificial offerings, the ancestors of such corrupt families also fall.
दोषैरेतै: कुलघ्नानां वर्णसङ्करकारकै: |
उत्साद्यन्ते जातिधर्मा: कुलधर्माश्च शाश्वता:।।
Through the evil deeds of those who destroy the family tradition and thus give rise to unwanted progeny, a variety of social and family welfare activities are ruined.
उत्सन्नकुलधर्माणां मनुष्याणां जनार्दन |
नरकेऽनियतं वासो भवतीत्यनुशुश्रुम || 44||
O Janardan (Krishna), I have heard from the learned that those who destroy family traditions dwell in hell for an indefinite period of time.
Well in some scripture, there was mentioned that Lakshmi devi deserts those places where, there are no traditions & duties followed. Where there are no festivites celebrated & where there are no sacrificing obulations offered to deities, and so on...
Thus, customs are indeed to be followed wisely.
I dont think a person can do anything these days if strictly follows those customs.
That's true as there are some customs which are too difficult to be followed either due to change of situations in current times or due to unsaid reasons. For an example, if the student gets an offer to learn abroad under scholarship, or supposed a diseased person can be treated overseas, thus as far as today's time is concerned no one will think about what scriptures says on going overseas.(might be the wrong examples to be put forth, but these are the most basic reasons why people tend to overlook shastras.)
Thus, Jagadguru Shankaracharya Sri Sri Bharati Tirtha Mahasannidhanam of Shrungeri math said this in one of this sermons,
"If one unable to follow the customs & rules laid in scriptures, for them Bhagwan naam jaap is ultimate solution. They must take refugee in naam jaap, as it not only compensates for sins arising due to not following scriptures but, also opens the doors to liberation".
(Those who can follow customs, they must definetly follow those as far as possible).
कालिकार्पणमास्तु ।🌺