The Stellar network actually can proceed +/-1000 tps. The consensus protocol runs through xy servers. If mass adoption of cryptocurreny happens will the scalability issue more or less automatically be solved after time by running more servers and guarantee transaction speed of 2-5 sec.?
Current maximum TPS rate is determined by the following constraints.
1. Maximum number of transactions per ledger
Configurable, current value is 50.
Defined in the protocol version, may be altered by the SCP (the set of validator nodes). Each Stellar Core node can vote for this parameter. The process is identical to the recent protocol update when the base reserve was reduced from 10 XLM to 0.5 XLM.
2. Maximum number of operations per transaction
Hard-coded, current value is 100.
Constant chosen by the Stellar dev team, may be changed by Core developers.
3. Average ledgers per seconds rate
Dynamic, 4-5 seconds per ledger on average.
Depends on multiple parameters, including the network latency and particular validator performance. Potentially can be optimized by 30-50%.
As you can see, Stellar has a wide range of options for maximum TPS increas. In the simplest case, validators can vote to increase
max_tx_set_size parameter from 50 to 200 and achieve the 4000 TPS even without source code modification.
Of course, a higher TPS rate implies higher validator hardware requirements, but server performance grows annually, so it won't be a problem at least in short-term and mid-term prospects.