It is not true tele-coils in hearing aids will be phased out and/or that it is only accessible to a few people.
You need to make sure that the hearing aid has a tele-coil and it is activated during the hearing aid setup.

Unfortunately due to inaccessibility of venues many do not have loop-systems installed. 

It is well known that the majority of hearing instruments worldwide have tele-coils fitted as standard. Feedback that we have received is clear that it was and continues to be a requirement for all devices on tender to have tele-coils. When devices are shipped to South Africa, the manufacturers do not take these coils out. 

We are curious to know what research shows that most devices are not fitted with tele-coils, as this runs counter to the experience and knowledge of the industry and devices worldwide.
The rights of a Hearing Impaired Person.
In the same way that one won’t ask a person in a wheelchair to bring/build their own ramp to access a building, one would not expect for a person with hearing loss to make their own accommodations for their hearing loss in a venue. 
A person in a wheelchair needs both the wheelchair, as well as the ramp for access.
A person with hearing loss needs their amplification device, as well as assistive devices and technologies like loop systems, captions etc. in order to communicate and participate fully in society fully. This is a human rights issue and in line with the Promotion of Equality and Prevention of Unfair Discrimination Act of 2000 (Section 9). 
A modern and inclusive approach would be for all stakeholders to exchange information and for the built environment to be designed with inclusivity (of all disabilities) in mind. 

See two links from the HIA and also Hearing Loss Association of America (HLAA) that explain more about the loop/tele-coil system that may help others to understand more about the technology:

Healthy Hearing Report 
• https://www.healthyhearing.com/report/45927-Hearing-aids-in-loop

  Hearing loss association of America 
• https://www.hearingloss.org/hearing-help/technology/hat/hearing-loop-technology/
• Assistive product specifications and how to use them.
• Preferred profile for hearing-aid technology suitable for low- and middle-income countries.
• WIPO Technology Trends 2021: Assistive Technology
* https://apps.who.int/iris/handle/10665/207694?locale-attribute=pt&mode=full