They are still effective if deployed correctly. That entails using a "combined arms" approach where the tank is supported by infantry, stationary artillery, advanced recon, etc. Aerial support from helicopters can be very useful in spotting and taking out tank killing teams, although they have their own vulnerabilities: if the opposition has javelins they also probably have some type of SAM. But that's where recon and good Intel along with infantry come in: address the threats to heavy hitters like tanks and air support so those heavy hitters can do their job.
It's hard to know exactly what's gone wrong for Russia in Ukraine, but the reports we're getting point to a huge failure to properly implement combined arms & close support tactics. It seems Russia either didn't anticipate the need-- thought they'd flatten their way to Kyiv so fast it didn't matter-- or their forces consist too much of undertrained non-professional conscripts. The conscript tour of duty in Russia is really too short to hammer home complex tactics and discipline for this sort of thing. 12 months is just too little time to game out the variety of scenarios they might encounter, and so when the one they were (presumably) trained for in this invasion meets initial resistance they don't know how to react. And that's before the logistics issues enter into things... Unfortunately that means Russia may fall back to simply bombing things to rubble and picking up the pieces. It looks like their plan was to take the country & install a friendly government fast enough to keep infrastructure and cities mostly intact, but now that that has failed it looks like they're moving towards the "rubble" approach which does not require the same level of ground training and tactics. Air superiority and long range artillery by Russia can do that.
It's hard to know exactly what's gone wrong for Russia in Ukraine, but the reports we're getting point to a huge failure to properly implement combined arms & close support tactics. It seems Russia either didn't anticipate the need-- thought they'd flatten their way to Kyiv so fast it didn't matter-- or their forces consist too much of undertrained non-professional conscripts. The conscript tour of duty in Russia is really too short to hammer home complex tactics and discipline for this sort of thing. 12 months is just too little time to game out the variety of scenarios they might encounter, and so when the one they were (presumably) trained for in this invasion meets initial resistance they don't know how to react. And that's before the logistics issues enter into things... Unfortunately that means Russia may fall back to simply bombing things to rubble and picking up the pieces. It looks like their plan was to take the country & install a friendly government fast enough to keep infrastructure and cities mostly intact, but now that that has failed it looks like they're moving towards the "rubble" approach which does not require the same level of ground training and tactics. Air superiority and long range artillery by Russia can do that.