Post COVID almost every single consumer business has seen a spike in the proportion of online revenue. Till FY20 this was 3-5% on an average, today it is closer to 10-12%. So yes, D2C brands have a much bigger pie to target today than they did 2 years ago and should logically be a bigger threat at the upper end of the price range.
Innerwear as a category traditionally had a few challenges, low ASP compared to other garments makes unit economics challenging in a store front at low volume compared to selling shirts or trousers. A customer walks in and goes away spending 500 rs on an average, at a retailer margin of 25-30% an innerwear only store will struggle to break even. Hence this was always sold in mom and pop hosiery shops where display space was limited, when the shop owner controls what brands gets seen, it made more sense for innerwear makers to give channel incentives than to spend too much on branding.
Jockey kind of changed the game in India, using Caucasian models to advertise and emphasizing US parentage allowed them to target and capture the urban segment above the economy range. Some of the best known Indian garments brands are named Allen Solly, Peter England, Van Heusen and Louis Phillipe for a reason 
With this happening and picking up pace post 2000, innerwear started to morph into a purchase with aspirational undertones compared to a purely utilitarian purchase.
The old economy innerwear makers like Lux, Rupa, VIP who were heavily distribution led started investing into building contemporary brands. But even today, they are stronger in semi urban and higher end of the rural market than in the urban and metro centers.
D2C is basically the next wave where new economy brands can tap into and service demand through the online model for a start, build scale and eventually move to an omnichannel approach. D2C is largely an urban and metro phenomenon so far because that is where consumers are willing to pay a premium for a differentiated value proposition. Almost all of the well known D2C brands are playing at the premium end of the market than at the economy and semi premium end. Hence, D2C brands are competing with the MNC brands like CK, Hanes, FOL and Jockey premium rather than with the economy segment heavy Indian brands like Lux, Rupa & Dollar.
Obviously the managements known this well and almost everyone is doing category expansion across athleisure, loungewear, women’s innerwear, leggings and casual wear in addition to investing into building channels across EBO, LFS, MBO and online.
It has not been easy for a standalone innerwear maker to scale in India. In spite of being well funded the new age players in women’s segment like Zivame, Clovia, Pretty Secrets have found it difficult to scale past 150 Cr revenue. The fastest growth in the overall innerwear category has been done by Van Heusen purely because they are leveraging existing EBO network rather than having to build channels from the scratch.
D2C brands will grow but are unlikely to be a threat anytime soon, especially at the economy and semi premium segments. Most listed players in India play here and not in the premium segment where the price points are INR 500+
)