There is no black or white answer here. Few variables that matter are 1) Tenure/experience of the staff 2) Role/function played by the staff 3) Security infrastructure 4) STPI/Government regulations w.r.t Intellectual Property
As much as the IT services companies want to get billed, the clients would also want to keep the working going. Most mature and established clients and IT vendors go through a legal and risk review before the work is transitioned, this should address data privacy and security. If the function involves dealing with personal identifiable information or any sensitive data then the work environment will also be restricted - ideally speaking. However if the work involved does not involve sensitive data + the vendor has proven security infrastructure + the people are experienced + have a good visibility of work without close supervision, then I don’t see why they can’t do WFH on a longer term. There are many if’s and but’s but one should not rule out the possibility.