Let's talk nominal:

Right now, the block reward is 25 BTC x $250 / BTC = $6250.  In 2032, the inflation rate should be be 0.78 BTC / block.  Each bitcoin would then need to be worth

   $6250 / 0.78 BTC = $8,000 / BTC

to achieve the same security ignoring transaction fees.  $8,000 / BTC is a very modest price if we assume this level of growth.

But transaction fees would no longer be negligible and will help improve security too.  If there's 2,000 TPS in 2032, that's 1.2 million transactions per block.  Ignoring the block reward now, the average fee required to maintain the current level of security is:

   $6250 / 1,200,000 txs = 0.5 cents / tx.

This is a very affordable fee, and still gives the same security level as today even ignoring the block reward.

Any way you slice it, if we assume continued growth, the network security should be greater in 2032 than now.