Bhashya
यावज्जीवश्रुत्यादिवाक्यानामन्यार्थासंभवात् क्रियावसानएव वेदार्थः; ‘तं यज्ञपात्रैर्दहन्ति’ इत्यन्त्यकर्मश्रवणात्;जरामर्यश्रवणाच्च; लिङ्गाच्च ‘भस्मान्तं शरीरम्’ इति; नहि पारिव्राज्यपक्षे भस्मान्तता शरीरस्य स्यात् ।स्मृतिश्च—‘निषेकादिश्मशानान्तो मन्त्रैर्यस्योदितो विधिः ।तस्य शा-स्त्रेऽधिकारोऽस्मिञ्ज्ञेयो नान्यस्य कस्यचित्’ इति; स-मन्त्रकं हि यत्कर्म वेदेन इह विधीयते, तस्य श्मशानान्ततांदर्शयति स्मृतिः; अधिकाराभावप्रदर्शनाच्च— अत्यन्तमेव
In plain words
Since the 'as long as you live' texts can't mean anything else, the Veda's real point is that ritual duties run all the way to death — you can tell, because it also mentions the final rite: 'they cremate him with his own sacrificial vessels,' and it mentions duties lasting until old age, and it gives the telling phrase 'the body ends in ash.' If full renunciation were the whole story, that cremation could never happen. And tradition agrees: 'whoever has a rite prescribed by mantra, from conception all the way to the funeral pyre — his obligation runs exactly that far, and no further for anyone.' Because tradition shows that any rite the Veda prescribes with mantras ends only at cremation, and because it shows plainly that no one is exempt before then — entirely, indeed...
Close to the Sanskrit
Because there is no possibility of another meaning for the statements beginning with 'as long as one lives,' the meaning of the Veda is precisely the termination of ritual action — because of the mention of the final rite, 'they burn him with the sacrificial vessels'; and because of the mention of the duration until old age; and because of the indicatory mark, 'the body ends in ash.' For, on the position of full renunciation, the body's ending in ash would not hold. And the Smṛti says: 'For whomever a rite has been enjoined by mantras, from the impregnation-rite to the cremation ground — his qualification for this is to be known accordingly, and not for anyone else.' For the Smṛti shows that whatever mantra-accompanied rite is here enjoined by the Veda has its termination at the cremation ground; and because it demonstrates the absence of qualification beyond that — entirely indeed...