I'll assume you don't know that reimbursement to bus companies for having £2 fares is based on pre-Covid data. The average fare before the capped fare came in was £2.80. Given the increase in bus running costs (esp. wages), commercial average fares would now be well over £3 (and the taxpayers' subsidy would have to be going up to keep it at £2). The scheme is voluntary - so if bus companies don't feel it's worth it, it would die anyway (some never participated, some only did it because competitors on a route did).
The industry has been anxious about an exit strategy for a scheme originally intended to be for a few months.
What Thatcher did is absolutely relevant. Despite this increase in a capped fare, the principle is still the same. If you want taxpayer-subsidised public transport, it would be silly to vote Tory.